I actually think it might be something closer to this:
de Gea
Wan-Bissaka Varane Maguire Malacia
Casemiro Fred
Sancho Bruno Rashford
Weghorst
Ideally bring back Dalot & Shaw against Forest if fit. Rest Casemiro, Bruno, and Rashford against Forest to start McTominay, Eriksen, and Garnacho. Utilize the substitutions well. Hopefully Martial is back then too...
Really want to see Sancho back in the side as he could be key to our season since only Rashford is providing goals at a high rate. I'm probably optimistic there though and Sancho will come off the bench here and maybe start against Forest if he's ready.
The 'weakest' line-up we used this season was probably against Aston Villa at Old Trafford in the League Cup. Which was:
Dubravka; Dalot, Maguire, Lindelof, Malacia; McTominay, Fred; Bruno, van de Beek, Garnacho; Martial
If Dalot & Martial are still out (with Donny) then it kind of limits who can really be rested anyway. I don't expect Pellistri, Elanga, Zidane etc to start but maybe come off the bench.