I kept track on my second playthrough, too. Here is what I found out. Some of them are duplicates of yours, and some are possibly missing still.
Spellbooks found followed by [who I gave them to]:
• Poisoned Splash (6MP-ALL enemies) minor H2O dmg [Busho or Caius]
• Earth Spirit (16TP-ALL) Poison Immunity, minor heal, less dmg from Earth [Busho]
• Fire Bomb (25TP-ONE) [Lilith]
• Zync Field (18TP-ALL) Cure confused, 55% magic dmg, ATK/DEF debuff immune [Genevieve]
• Elven Thunderbolt (13MP-One) Give to PS who knows another Thunder spell for Xtra DMG [Genevieve OR Audrey]
To give the book to Audrey requires she be in the Volcano/Dark Shrine with Busho leading the Party because Caius doesn’t take any items with Penelope and him.
• Fairy Dash (19TP) Heals ca. 300+HP and cures Paralyzed, Stun [Genevieve OR Audrey if "alternative" ending is planned.
• Fire Spirit spell for protection [Busho because he typically acts first]
• Dark Scroll (In Evil Shrine) Gives Dark Blast which hits ALL enemies and poss. “Curse”
Hammerhold spell given for
completing Q#22. More DMG to Hard Hitter enemy and if PS has higher AGI. (Better for Busho)
Gravitabomb – Given after defeating Slime King in St Town/Mtn area. Great for Busho.
Given to the character who has highest MHP and also is fully healed. Let Caius' HP drop so Busho gets this one. There is a thread that talks about this one.
Frenzy learned after encounter w/ Lord Gomorrhean and Murder Orc on Elven Forest Bridge.
It is apparently given to character with lowest HP after battle. This will require some planning if you want to have Caius learn it so he can use Mace of Megadeath more often.
Note: The following spells can be acquired without notification when changing levels after completing Quests, and do not appear on screen such as they do after battles.
CaiusLvl. 1 Skill – Power Crush
Lvl 3 Magic- Heal (+40% HP, 1 PS)
Lvl 5 Skill -Love Bam
Lvl 8 Magic- Gadameon (max this out as poss.)
Lvl 10 Skill – Rebel Rush
Lvl 11 Magic – Scaleburst (Fantastic spell and ALL enemy damage eventually after getting above Lvl 6)
Lvl 15 Skill – Mace of Death
Lvl 22 Skill – Mace of Megadeth (max this out as poss.)
MarlynLvl. 1 Magic – Sexy Heal (+60%HP & cure Poisoned & Charmed)
Skill – Kiss of Charm
Devour - Optional if she eats Gerald before getting Busho
Lvl 3 Magic – Thunder Boom Boom (All enemies)
Lvl 6 Skill – Varnished Scratching
Level 9 Magic – Kiss of Death
Level 12 Magic – Ensorcellor
Busho (starts Lvl 3)Lvl. 3 Magic-Detox
-Orc Grimace (Max this one out to lvl. 12)
Lvl. 3 Skill - Taunt
Lvl 5 Skill - Zephyr Blade
Lvl 9 Skill – Rain of Hits
Lvl 12 Skill - Taunt of all Taunts
Lvl 14 Magic – Tippi Toe
Lvl 15 Skill – Price of Blood
Lvl 17 Skill – Opening Act
Lvl 20 Skill – Finisher
Lvl 23 Magic – Slicer
Genevieve (Starts Lvl 11)Learns Fireball if equipped with Dragon Cane weapon
Starting Magic:
Worms Hatching
Items Synthesis
Witchcraft
Starting Skills:
Burst of Poison
Aquavirus
Lvl 12 Skill – Zero Zombie
Lvl 13 Skill – Cyclus Syphonus
Skill – Tortoise - Effects: AGI 50%, but 160% DEF and 150% MDF
Learned from talking to tortoise in SR#22 before opening chests
Lvl 16 Skill – Soil of Abondance
Lilith (Dark Elf Starts at Lvl 17)Magic:
Poison Cloud
Dark Cloud
Acid Rain
Skills:
Rain of Arrows
Snip Out
Lvl 19 Magic – Herbal Knowledge
Lvl 20 Skill – Canopy Wind
Lvl 22 Skill – Stumping Arrow
Lvl 25 Skill – Geyzer
Penelope (Starts at Lvl 21)Magic:
Heal
Purification
Revive
Aura
Saint Dissolution
Grand Protection
Skills:
Meditation
Zomboid
Scepter of Justice
Holy Knight
Wind of Wisdom
Dead to Dust
Damnation of the Damned
Wisdom Kills
Audrey (Starts Lvl. ????)Only if found by Busho’s party, can she gain any additional spells from books.
Magic:
Lizard Blast
Thunder
Mega-Thunder (All)
Thunder God (All)
Skills:
Multi-Hits
Dragon Queen (self only)
Rush
Super Jump
Lobster Crash
Nyx (Starts Lvl. ????)Magic:
Heal
Consumating Metal
Piercing Spear (must have spear equipped)
Overboost
Shield of Jovan
Skills:
Undead Slayer
Orc Beheading
Dino Crush
Valkyrie Slash
Nyx (self heal only)
Please feel free to edit, combine, or comment on any needed changes.