For a live performance I recommend not using the laptop for mixing/processing.

Instead, Get a small, inexpensive hardware mixer and a pair of powered speakers. Plug in the mic and your instrument if you have one, input the music from the laptop or whatever music player you choose. Use WAV files if possible, premixed, and missing the parts you are going to play. This will be the easiest way to perform and you won't have any latency. I also recommend carrying a backup source for the music files, even if it's only a phone or a MP3 player.

You want your live performances to always be as simple and fool proof as possible. Trust me, I played a lot of live gigs in my time and keeping it simple always worked the best.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.