Maybe it makes sense to focus on the players where there seems to be some chance they will be in ten Hag's plans this following season. Ie, the players that aren't known to be deemed surplus to requirements, and who aren't actively trying to leave the club, and who aren't loan players who might or might not fit into things. If so, that leaves this:
GK: Dea Gea, Heaton
LB: Shaw, Telles
RB: Dalot
CB: Maguire, Varane, Lindelof
CM: Fred, McTominay
No 10: Bruno, van de Beek
Forward 3: Rashford, Sancho, Ronaldo, Elanga
That's a lot of holes to fill - at the very least, a RB, a CB, 2 CMs and 2 forwards. There are 3 ways to fill them: Acquire new players, bring in loan-returnees or academy players, or keep players you ideally want to sell (or who ideally want to be sold).
GK: Whatever happens to Henderson, we're set. For now. But sooner or later there's a question if you can really continue with a GK who is so little involved outside his own line as de Gea is.
LB: Probably not a priority area.
RB: AWB evidently to be sold. Williams and Laird are options, but the trouble is we really lack a credible starter. I don't see how this could not be a significant problem area if we don't bring someone in.
CB: Holdovers: Bailly is centre of discontent and must be ditched, Jones wants out and is right to want so. Returning loanees: Tuanzebe, who did little to indicate he's got a United future. If they all leave, then we need another body in central defence, we can't just have 3. There is also a case for upgrade (ie, a starting XI level player), but I'm not sure if there's a compelling case that should trump several other needs.
CM: Here we're already two bodies short. DvdB can play there, but presumably EtH wants to use him further forward. Garner and/or Mejbri may make the cut, but are hardly the go-to options. Perhaps there's enough that we could make do with one new player, if so, that needs to be the most defensive holding midfielder, where we have no one credible. If there's not two new acquisitions, then Fred is essentially a regular starter.
No 10. All set. Not only do we have Bruno and Donny, also Mejbri may be in the mix?
Forward 3: This looks to me like the area where we have maybe the biggest holes. Two players short. Martial is the holdover who could fill one of those two slots, but given how clear he's been about wanting to leave (not to mention how bad he's been the past two seasons), it seems like a stretch to imagine another dawn for him at United. Diallo and Pellistri returning loanees, but neither seem plausible options for regular playing time. Then there's Garnacho, who may or may not fill such a spot.
You see why Timber is an attractive option - he'd solve issues at both CB and RB.
It looks to me like making this work reasonably well would require at least 3 new signings (CM, Forward, RB), and preferably 5 (another forward and another central midfielder). The RB and both CMs should be starting XI quality, the forwards don't necessarily have to be. While upgrading at CB and in goal (and replacing Ronaldo) would have to wait for next summer, at the earliest.