A few thoughts on the defense:
Flexibility.
1. Noted earlier, but Furman is going to have a lot of mix and match options on the defensive front. We've got size, pass rushers, run stoppers, and depth. We are big enough to play two gap, fast enough to play one gap. I don't think you'll see many FCS teams with that sort of flexibility up front.
2. I was intrigued by the note that Achina moved to ILB, but can play both SPUR and ILB. I doubt that move was made for depth purposes, because we are really deep at ILB and have only 3 players listed at SPUR, two of which are seniors.
It could be you see Furman shift their focus a little bit. Furman seemed to modify the position a good bit last year. Jalen Miller was the primary option at SPUR after Achina's injury, and more often than not, he was essentially lined up more traditional SAM linebacker. For instance, here:
I doubt the roles really change. I suspect that if Furman wants more pass coverage help in a situation, they'll turn to a designated nickel corner (which Chizik has largely handled the last few years). If we prioritize a bit more beef up front, you might see Achina or Miller step in. With a healthy Achina and veteran Miller, Vaughn can probably get even more creative with these looks.