Has a team full of 3* and walk-on kids ever won an MNC?
well, your 10-0, I would think the majority of the fanbase is thinking about it.
there's been some teams that have gotten close at least. I would guess Washington from last year is not loaded with 4 and 5 star talent. This Miami Hurricane team this year probably isn't. Oklahoma St has been close, they probably aren't. TCU I'm sure isn't they were ranked 5th a couple of years ago. Michigan St was in the playoff with a bunch of 3 stars. So, I guess no one has maybe won it recently, but there's definitely teams that are close.
After Alabama, Ohio St and Clemson, there's probably a next tier of 5-10 teams like OU, USC, Notre Dame etc
Then you have a bunch of teams after that, your TCU's, Oky Sts, Oregon's, Wisconsins, Michigan Sts that are certainly capable.
It's certainly doable, but you are gonna have to be pretty sound in most phases of the game. you can probably win with a couple of issues, like an average QB but then the defense and special teams probably need to be excellent. If Ohio St can win with Craig Krenzel, I guess there's hope for Hornibrook. But Krenzel was more of a RB, game manager. If Hornibrook can limit mistakes, and be a guy that throw for 12-for-18 for 150 yards, no picks, it might be doable