A) Server: ???

Given the current state of Matrix server landscape, i am afraid there is not a single server i would recomend. For the time being i am still using Conduwuit (see here) but thinking of trying out Dendride or switch back to Synapse (see here).

I really wish Matrix had a more diverse implementations since both Synapse and Dendride has been moved back from the Matrix foundation to Element ownership, and i don't like that.