Really hope Bergvall is fit to start over Sarr but imagine its fairly unlikely and we'll be lucky to see him on the bench at best.
I think the team picks itself. Its a cup final so you have to side with pragmatism. Throwing Odobert or Son into the 10 would be a huge gamble which I don't think we need to take, we'd quickly find ourselves with massive gaps and probably end up playing a 4-2-4 if Odobert/Son get lost during the game. Sarr has to start if he's fit and Bergvall is not ready. If neither are fit then I'd go with Gray!
My idea is Bentancur should be pushed into the 10 with the other 2 sitting. Or else have Bissouma sitting with the other two playing as 8s. Yes, there is a real lack of creativity in this midfield but this pragmatic approach in midfield will allow Porro and Udogie more license than ever to get forward and attack. We'll have at least 2 DM's covering at all times.
My preferred team is the below:
Vicario
Porro Romero VDV Udogie
Bentancur Bissouma Sarr
Johnson Solanke Son
Bergval can start over Sarr if fit and play in the 10 with other 2 sitting.
Richarlison and Tel should both make a big impact off the bench. We can try Odobert in the 10 if chasing the game and desperate.