Yeah, we did that.
But it wasn't even a computer, it was a Roland workstation driving everything you mentioned, including the lights.
Running MIDI isn't much of a challenge, I'd still do it.
Running multitrack audio files is a whole 'nother animal.

We brought a computer along to 'record' the shows, but that was it. The show wasn't run from it.
If it stuttered during the recording that's no big deal; we were the only ones going to listen to it and analyze it anyway.

Eight subgroup outs from the mixer to a 1010 interface and into Powertracks.
Ahh, those were the days .. I wish we'd kept some of those files to look back and laugh at

I do not work here, but the benefits are still awesome
Make your sound your own!