Quick demo recording - URGENT

We finally got the 4 of us together to start a band, and straightaway a guy wants to give us a gig but needs to hear a demo "tape" first.
I have a scarlett 2i2 interface which I use at home for personal use with backing tracks and audacity, or occasionally someione will send me a piece to lay aline over.
Anyhow - will this suffice for demo in the practice studio?
Is there an app that might do the a good enough job on a smartphone (android) - never used sucha thing before

Urgent advice greatly appreciated