Quick couple of questions first:
1) Do you have a drummer?
2) Has you keyboardist have any keyboards with sequencers on board?

If the answer to question 1 is yes:
Well the drum will have to be able to play to a 'click track' and this is a very hard thing to do! Headphones will be required as he need to hear it loud enough to over come his own drums, but you don't want the public to hear it. Go out of sync, or lose track of where you are in the play back of the sequence, and you will have an audio train wreak.

If the answer to question 2 is yes:
Makes life slightly easier, as the keyboard player can set the sequenced tracks in montion, but you'll still need to keep very good time, and know exactly how the track goes, the sequencer will not make a mistake, and it will be unable to 'follow you' if you make a meal of things. With a drummer on board, you'll need a have a special audio send from the controlling sequencer/keyboard as their click track.

To sum up, it's not for the faint hearted.
It might be worth looking at the instruments you have and changing them to match the style of music you want to play:
Electric kit for the drummer?
Synth for the bass player to play synth bass lines on, or a processor on his bass to make it sound more like a synth than a bass?
Or even guitar synths?

Playing a mini-disk and miming is NOT an option!