I'm less bullish than you on the answer at QB being in-house (only because I've basically never seen Nickel play - and evidently he was behind Williams, a guy that has proven he can't play), but TE is a different story.
Unless Shockey / Olsen et al is walkin' through that door via the Portal I'd be content to go with Lofton, Gilbert, Schott, Briggs and Mueller. At some point you have to trust your high school recruiting and show players that they're going to get opportunities to play here.
I have the same opinion at DE.
I really like all 3 of our Young TEs - Schott, Gilbert, and Mueller (Briggs too but he'll RS). But obviously you don't expect Mueller to contribute right away. Schott and Gilbert should both imo be counted on to be heavy contributors next year. We need to develop them and they have the talent to be legit. So force them out there imo.
But this is why I'm saying to maximize this roster imo you just move Lofton to HB/FB - the position EVERYONE was saying he was best at in practice - you let Fletcher / Brown leave.... then you bring in a do-it-all TE. That way you have a high quality portal TE as starter, and we consistently run a lot of 2 TE (and will run a lot of 3 TE if we are confident in their blocking). So Schott and Gilbert getting heavy rotation. And Lofton can be our big back and actually better than Brown/Fletcher on 3rd downs because he'd be a real weapon in the pass game. Fletcher was very good in his role this year. but I think Lofton could give the same net contribution.
I'd really like an offense of
QB: Portal / Nickel / Coleman
RB: Pringle / Lofton / Portal RB3 / CWH+Mallory
TE: Portal TE1 / Schott + Gilbert / Mueller / Carve+Briggs
X: Moore / Wingo / Chance / Parris /
Slot: Toney / Carr / Spafford /
Z: Trader or Portal / Upshaw /
LT: Bell or Samson / Ervin
LG: McCoy
C: Portal / SJ /
RG: Samson (if Bell returns) / Kinsler or Buchanan
RT: Cantwell