I think the only “needed” studio is NetherRealm.
Otherwise I’m sure Microsoft would do its due diligence to check the others too to see if they’d fit in well.
The problem is with all the mismanagement, scandals/turmoil, and people leaving from all these studios over the years, I feel a bit hesitant saying all of them should be grabbed (and this is coming from someone that loved the Arkham trilogy and SoM).
Otherwise, nothing is stopping Microsoft from poaching talent to build new teams instead, because that may be surprisingly more efficient depending on what’s going on at these studios.