I see that kombucha exists and is identified in EMI, but it has no recipe and isn't even in the creative menu, was it simply removed, or is there something I am missing?

Kombucha is crossover content when you have Farmer's Respite installed.

It was always unobtainable without that mod present.

Similar to what BnC had, FR will be going through a major rework too, hence why we probably won't be porting it for a while.

Ah, I figured as much.