Bastan with the ?Painting, you don't ahev to reset the game for that. Just go in the shop with a few ?Paintings and talk to him. If the pop up menu for appraisal appears, close it, go outside and back in and talk to him again. Keep doing it until he mentions the Ivanov painting (which means the pop up doesn't appear) and you have him

There are indeed certain points that require for you to recruit characters or else you can't get them anymore. Keep in mind that Eresh doesn't have to be recruited, since she shares a SoD with someone else (won't mention who since it's quite the spoiler). But it's better to recruit Eresh, since she's more useful.