It's certainly important that all players, but especially the new guys, are grounded in what I consider the basics, and you've listed several.
Certainly these guys come from pressure situations in college. They should be aware of their assignments and surroundings. Understanding the basics - footwork, blocking, tackling technique and others must become second nature. Equally important is staying emotionally grounded. Belton's mind must have been on another planet when he pushed an opponent from their back well out of the field of play, drawing the yellow flag.
Personal fouls are gonna happen - but the deliberate fouls, where there are clearly better choices (like do nothing), must be avoided, ideally eliminated. I keep thinking of a Bengal playoff game from many years ago where a win was clearly within reach. I think it was LB Burfict (sp?) who committed two or three consecutive PFs and allowed the opponent to get into easy FG range.
That is best controlled from the top down. I was glad to see MLF join Belton on the way to the locker room after the 1H, and 5 penalties, and give him an earful. Better to nip that **** in the bud, and it clearly worked, he had a good 2H.
It's probably boring for these guys, but imo can't be stressed enough.