I do that all with Gig Performer and Ableton Live (Suite) - when you add M4L it is also working with Ableton Standard.
All my backing tracks are played by Ableton Live and program changes to external device could also be sent from Ableton Live,
I am using the so called Session View in Ableton Live so all songs are loaded at once and therefore the setlist can be switched on the fly without the need of reloading some things.
From Gig Performer I am sending OSC messages to Ableton Live, so each rackspace is in sync with the corresponding “scene” in Ableton Live.
LINK is activated in Ableton Live and Gig Performer and when I press play on my controller S88 MKII then Gig Performer global play is started (that is important because I automated switching of variations) and in Ableton Live the selected scene is triggered.
This way the main Controller his GP and all other things like sending out Midi Messages, playing Backing Tracks and automation of variation switching is made via easy scripting.
Complex controlling of widgets can also be done via Ableton Live and a M4L patch
Automate Gig Performer from Ableton Live
And here the forum entry where is described how that all is done: