I thought it might be helpful to put in one place all the unanswered questions that are scattered across different threads.
1. Can the Orb of Inferno and its Altar be activated?
2. Where does Samaritano disappear to? He reappears at the very end.
3. Can Toshida the boatman in Nivkaden be activated?
There may be links between these e.g. can Samaritano activate the Orb? Could the boatman take you to where Samaritano is? Of course, it could be that all 3 are teasers.
4. At what level does Tamara learn the spell ‘Ghastly Smirk’? I forgot to make a note of it.
5. Who else can she give Flake of Edelweiss to besides Jordan and Melusine? The play through where I had her had Anton and Shiro, but perhaps there is someone from another school.
6. Does she ever level up enough to cast it a second time? My sense of duty to finding out packed in after I’d laboured to get her to lv67.
7. Has anyone found another use for the ice cream? It stays available to be bought even after completion of the quest.
8. I think we now know that Anita can’t be activated to be a playable character, but there is still the question of whether having Alex in the party which completes her quest makes a small difference.
I think that's all the outstanding questions, but I may have forgotten something.