In previous PassTheGame challenges and in several of the recommended videos, the devs have either done or suggested pulling from previous dev experience on the project. IE if you already have a character controller script set up you can just pull it from there.
I don't think so, given it's encouraged by the devs and by the people they've linked. So long as you're creating a new project from scratch at the start (and not submitting, say, that JRPG project I started back in May) you're still following the rules of the jam.
