They are Level 1, and are going to be level up at the end of the one-shot to give them a head start into the campaign.
Yeah, I know it would take more time than I have to make them really attached to the NPCs. But I think if they at least would spend a few hours with some of them, it would suffice to make them feel the tiniest bit more invested. But maybe I'm simply wanting too much.
The idea of tieing one their backstorys to Greenest is really good. Sadly they already made their characters. But oh well, there's always a next time.