Here is what I want to do at a live gig: Start playback of a BIAB arrangement I am playing MIDI piano with, pause it after maybe a couple verses and then:
1) Start a loop of maybe just a drum brush kit and play along with it (MIDI piano or bass, or acoustic guitar or harmonica...) for a few loop and then resume at any time the BIAB arrangement from where it was paused, OR
2) Just maintain the paused BIAB playback and play an acoustic MIDI bass solo for 20-30 seconds (e.g. no drum kit loop, just silence from BIAB) and then resume the BIAB arrangement from where it was paused.

How can I best do this ? Would some hardware keypad controller like a a Novation Launchpad or Akai APC and just playing back a BIAB mp3 on any MIDI player be the way ? I'd like to keep it simple and reliable with a minimum of hardware for portability- maybe even on an iPad.

Bob