First, Jackson State absolutely would've been allowed in the playoffs but there's way more money in the Celebration Bowl.This year's champion will have a major asterisk next to it due to Jackson St not being allowed in the playoffs.
Second, no they won't. Jackson State would've been absolutely embarrassed by any of the top 5 in this round, most likely lost to William & Mary and Incarnate Word and would've had to play incredibly well to have a competitive game with Holy Cross. Seven single Valley team have offered them a home and homes over the last 3 years and they turned them all down because Prime knew he couldn't be exposed.
The SWAC is a god awful league that has always avoided the playoffs because they don't want to be exposed. That's fine, they certainly have a place in the college football world but not as a league that could ever produce a semifinalist, let alone a champion.
That said, Sacramento State and South Dakota State are the two best teams in the country. It's not close and the title game between those two is going to be lots of fun.