Several solutions to this. The most effective, I'd say, is to have the drummer trigger the Fx, using a MIDI pad. That way, the Fx are triggered at the right spot in the song, whether the drummer is faster or slower.
If, on the other hand, the Fx themselves have a specific BPM, the only real recourse is to have the drummer playing to the 'click'. I wouldn't like to think of the train crash if all the band are in sync with the keys and Fx, but not the drummer. It makes no sense.
I'm assuming that these are simply 'one-shot' Fx, such as a bit of sampled sound, and not a constant tempo-linked delay or the like..? If the latter is the case, all the band has to have that tempo available to them, and that really means that the drummer plays that BPM, with a click track, end of story. You all play to the drummer, including the keys. The Fx have to be set to the drummer's tempo. If his tempo varies during the song, change the drummer.
(Disclaimer : I'm a drummer...)