TLDR version - I liked it. You will, too.

Played on Normal Mode
Your opinion about Caius?Hmmm... immature, naive, narcissistic, reckless, shallow, yet he suddenly 'became a man' when the situation called for it. Not that he didn't fall back on those earlier characteristics throughout the game, but he certainly matured and stepped up to the plate. And later in the game, in the occassional regressions, there was always that wise woman to corral him to better choices.
Your opinion about Marlyn?Never liked her. Never trusted her. Was she a succubus or a slave? Wendala would be appalled at Marlyn calling herself a slave! Okay, so she was a reasonable, actually pretty good, fighter, but, yeah, definitely not a likeable character for me.
Your opinion about Busho?I liked Busho right from the beginning. I know there was at least one player who was annoyed by Busho's pessimism, but I found him to be the perfect balancing act for Caius' naive and foolhardy behavior.
Your opinion about Genevieve?My favorite character. I've only gotten just one ending thus far, so I don't know if the individual outcomes change with the second ending. I was kind of sad to see 'Geneve' just retreat back to her own mundane life.
Your opinion about Lilith?A strong woman, and like most strong women, there are some who will dislike her just for being capable. And she was more than capable. The romantic relationship that so subtley brews between Busho and Lilith is absolutely a Nora Roberts role reversal. I realize love interests aren't the focus of most RPG players, but I found this one to be of the most refreshing I've experienced in a long time. Don't worry, though. Hard core RPG gamers will not find this romance to be either sappy or excessive. A little aloof perhaps, slighly condescending, well more than slightly to Genevieve, but she is an elf after all and that's her nature.
Your opinion about Penelope?The game needed a Penelope. A question down the line asks to compare Penelope with Luciana. I'll do that, but here, I'd like to compare Penelope with Yveen. I do think that's a better comparison. Despite her reluctance to involve herself in worldly affairs, she decides that this time she must intervene and joins the party. Like Yveen, she is a strong healer. Like Yveen, she is bemused by and perhaps even has a crush on the young hero, though not in a romantic way at all. She takes it upon herself to nurture and protect the party and lead them to success.
Any opinion about the 2 optional characters (if you found them)?Nyx, another strong woman who doesn't take any guff from others. She's not quite as abrasive as Laxius Force's arena champion Linda, but she neither does she mince her words or suffer fools gladly. Not sure the trio would have been as successful if it were not for Nyx joining the party. And, unlike Lilith, Nyx seemed to recognize Genevieve's inner strengths. (As an aside, I'd like to know the history of Nyx. That name seems to show up a lot in Indinera's world... forum member, weapon in this game, mentioned in other games..)
The dragon lady, Audrey, is a supportive character at best. Not much to say about her, she shows up by circumstance and it's always good to have a third party throw some healing / boosting potions your way.
Who is the strongest character, and why? And the weakest?I think Busho is the strongest character. Caius is physically stronger, but Busho is a fundamentally stronger character both in terms of moral fiber and fortitude. The weakest, well that would be Marlyn both in terms of strength, moral character and fortitude. Honestly, it was an effort trying to keep her alive after rescuing her.
Who's more handsome, Caius or Busho?Too subjective to answer...
Who's the prettiest, Marlyn, Genevieve, Lilith or Penelope?Too subjective to answer...
Who hits harder, Caius or Random (Laxius Force)?Random has a much wider range of talents, so he definitely wins this contest. Not to mention, Random has both Sarah and Wendala, and even Luciana and Yveen when they're present, boosting him to even greater levels. Yeah, our young Caius will have to weather quite a few more demon outbreaks before he can stand on the same stage as Random.
Who is wiser, Penelope or Luciana (Laxius Force)?If you're talking 'facts or book smart,' then maybe Penelope, but even that's doubtful. Aside from knowing how to approach and defeat the demon, I didn't see much evidence of Penelope's sage wisdom. She is after all, in her own words, "a sage, not an encyclopedia." I will give her credit for recognizing Genevieve's worth, though. But as for wisdom, as in life experience, knowing what's best for people, pondering difficulties and then figuring things out, it's definitely Luciana. Although, like Caius vs Random, Luciana has had hundreds of game time hours to develop and display this wisdom, so the comparison might be a little unfair. They do both like cats.
What age do you think is Penelope?Oh, I think she is very, very old. Remember she told the group that she would be travelling incognito in her 'little girl' disguise. I think it would have been nice for her to reverted to her true sage self when they approached the final demon. It would have boosted her magic abilities, as she wouldn't have needed to keep some in reserve maintaining the disguise and it would have been a refreshing change from the villain always saying, "HA! You think you have defeated me! Now you will see me in my TRUE form!"
What's the best place to live, Fay (1st village), Deckersville (port town), Canacopra (Island village), Elven Village, Saint Town or Master Z' bunker?Deckersville for sure. It's not such a small town as Fay, and not as isolated as Saint Town and the bunker. Plus, you can always walk to Fay and take a boat trip to Canacopra if you so desire. Elven village? If you're an elf, I guess it's okay, but otherwise, I'll pass. They are, after all, elves.
Did you purchase the plant in Hermit Island village and if so, did you like it?It was okay. I think perhaps I didn't find as many recipes as was possible.
Your opinion about the story?Okay, so the overall premise was the old 'hapless chums find themselves in position of saving the world and they rise to the occasion.' But it did put a new spin on it as our 'hapless hero' DELIBERATELY released the demon. That was both fun and refreshing. As in most of Indy's game, the story served to develop both characters and relationships. This is a story, not just a hack'n'slash your way to the final dungeon game. And it's beautifully done so that even if you are a TLDR kind of gamer, the dialogues are spaced far enough apart, so it doesn't spoil your gameplay. Definitely a story to be told, but definitely an RPG game, NOT a visual novel. It's a nice balance.
Your opinion about the graphics and sounds?Graphics were a nice mix of RTP and custom graphics. I'm not a fan of chibi style, but I get that this is a fault of the game engine, not the game developer. Sound, well, I'm sorry Indy, but I play with the sound off.
Your opinion about the gameplay?Gameplay as in mechanics or development? For me, the game played very smoothly. I use keyboard controls, and I didn't have any issues. Neither did I have any issues with game freezing like some did. I should mention, though, Indy was very quick to research/identify/fix the game freeze as soon as it was mentioned, so it's likely not to be a problem to anyone now.
What was your favorite moment and why?The volcano blowing up because (1) Caius finally started acting like a hero and (2) I didn't have to deal with Marlyn anymore. Yeah, I really did NOT like Marlyn.
What's the game's best/strongest sides?Mountain cliffs? Or did you mean teams?
Favorite and hardest dungeons?The ice shrine because it was hard, but also gave good rewards in experience and gold. Also, the spawn rate of enemies seemed really balanced, enough to grind but few enough to quickly dash to the next screen.
Favorite and hardest sidequests?I did like those 'chain' sidequests, where you had to solve one to be able to solve a second. My favorite was the Pillar - Erin - Pristine.
Most dangerous enemy?King Slime and the Raflesia on the world map.
Who did you send to the Evil Shrine at the end?Caius and Penelope (with Marlyn and Audrey offering their services as well).
What did you think of the ending?I thought it was sad. I'm hoping that the 'two endings' means maybe I could have found a better ending.
How does this game compare to past Aldorlea epics (Laxius Force, Millennium, The Book of Legends, Witch Hunt etc)?Well, it's difficult to compare any game, except maybe the Millenium series, to Laxius Force. What are we talking here, 7 games overall? I'd compare it to other standalones like The Book of Legends and Witch Hunt. Witch Hunt was cute, probably didn't take as many hours to complete as Forever Heroes, and definitely didn't have the number of locations / bosses / sidequests. I remember liking the Book of Legends, but, honestly, it was a long time ago, and I don't fully remember it. I would say that Forever Heroes holds its own against any of the standalones, and that's not to disparage the others, they were all quite fun to play, but Forever Heroes is just a notch better in terms of overall gameplay.
I would also like to mention that Indy specifically stated Forever Heroes was designed to be a 'short' RPG with his intention being learning a new game engine. Well, this 'short RPG' certainly took off with a life of its own and developed into quite an epic experience. Hats off to Indy for yet another wonderful game.
Also, since I was fortunate enough to be in the company of early players, I'd like to give a huge shut-out to @kimo, @lilac, @MerryX, @jirafa, @jincyk, @aggeliki, @darkange, @littlebro, and anyone else I may have missed. Your hints and tips have been greatly appreciated and were certainly instrumental in a successful first playthrough.