Periodic

Second Chance is actually afaik an ability on armor. Eder's Saints War armor has it, and there are other items that have it. It may be a bug, but you can't survive a total party kill if the last person to be knocked unconscious has Second Chance, there has to be someone else there. Bug or not, that's the current implementation.

Monster kills don't give experience, though. Are you saying that animal companion kills fill out the bestiary?

I believe this has to do with the fact that the spell scroll has to be used in combat. Even if you have enough lore, for some reason the scroll with show the lore requirement as red because it's a combat spell. If you put it in your quick slots and start combat, I believe you'll be able to use it.