Though I would like to see some crossover involving the FSN cast since they already incorporated Ryougi Shiki
Assuming that Fate/Extra is based on the heaven's feel ending, youl get your Touko/FSN crossover eventually. (GL Rin)
As for melty, yes. leave it as tsuki/knk. This isnt battlemoonwars, the grailwar isnt going to happen in fucking misaki town. servants = no.
Also, question. When exactly does melty take place? cant remember for the life of me. (IIRC F/SN was 2+ years after tsuki. So unless melty is more then 2 years after tsuki, then F/SN hasnt even fucking HAPPENED yet. XD)
Well, its because FSN and Tsukihime occurr in seperate universes. I'd love to see Shiki vs Archer-arm shirou or UBW Shirou even though its already been said that it would just end in a tie since Shiki would die from overusing his death perception and shirou would fry his brain from tracing