I think Konate is cheaper than Upamecano too and a year younger.
I'd personally opt for Konate, United just need an energetic CDM in-front of them.
With Caicedo (if he signs) he has a good passing range it looks like, and lots of energy, 5'10 he would cover some ground in games.
A back four for United would typically look like:
First choice team
Centre-backs: Maguire, Lindelof, Bailly, Konate (?)
Full-backs: Telles, Shaw, AWB, Tuanzebe (preferred at CB but he can hopefully play on the right when the opposition is an aerial team).
Sell: Jones, Rojo, Dalot
Defensive Midfielders
McTominay, Fred, Matic, Caicedo (if he signs)
McTominay and Matic are the physical CDMs who are a little more aggressive, Fred and Caicedo are the ones who are a little more energetic for quicker temp teams.
I don't actually think we are far off in defense or defensive midfield, I think it's just one addition to each on this point.
My reservations with Bailly is injuries in general, if he can stay fit its great for United honestly.