I think Belichick will be a good coach at UNC. Not great, but good.
I think the choice of Lombardi as GM is laughable. I understand that BB covets/requires total control over the program, and that Lombardi is just a puppet. Outside of that, the hubris of this move cannot be overstated.
If one assumes the Transfer Portal is the college equivalent of NFL Pro Scouting, recruiting is the college equivalent of NFL Amateur (i.e. college) Scouting, and that NIL is the college equivalent of the NFL salary cap (maybe a reach here), then after Year 1 this will be a disaster in terms of team building. BB's talent acquisition record with the Pats was spotty at best the last decade he was in New England. Lombardi's only college experience was as Recruiting Coordinator at UNLV from '81-'84 (40 years ago!) and he sucked as an NFL GM when he was in that chair. Aside from a probable Year 1 bump for transfers looking to polish up their resumes for the NFL (a la Indiana), I think talented kids will figure out real quick that UNC doesn't have the bag to compete with the big boys, and that Lombardi and BB are over their skis in this regard.
On-field coaching and week-to-week gameplanning? Coach Bill's wheelhouse. Program building? No longer his strength and he has no experience at this level. I think the results here will be super underwhelming. But good for him.
I also laugh thinking about him identifying and developing QBs and WRs at this level. You think 18-20YOs will run option routes to his satisfaction? Haha. He'll be fine coaching all the other positions, but the talent base will probably never be any better than mediocre after this potential Year 1 bump, imo.