No worries about the wall of text! I really enjoy writing and thinking about these games, so I'm glad mine is worthy of "The Wall" :)
1: Huh... Excellent question. I would let the player choose for now, but I'll look into clarifying that.
2: Players have a max of 4 Chapters from Tales. After that, they only gain new features from adventuring , so the max combatant bonus is 4 (though they still gain max Hope and HP from levels). If someone wants more bonus to hit/damage, they'll need a magic sword or the blessing of an archpriest, or something similar, whatever's available in the world.
3: While sorcerer magic *is* more dangerous, it is also unlimited. Wizards start with 1 guaranteed spell per day, but sorcerers never run out. This is why for a sorcerer, the spells are so much more dangerous. The question isn't when they'll run out of magic, but what chaos they'll unleash as they tap into it.
I hope that all makes sense, and again, thanks for the feedback!