Maybe I could put both the mp3 and the guitar through the Ableton? It's the two channel model. Then, I'd hear the mp3 thru the earbuds and the guitar via leakage around the earbuds.

I could split the guitar signal and play one side through an amp in the room. I'd have the mp3 of the backing track on my phone, but how would I hear the guitar? If I monitor from the laptop, I'm going to get some latency. That might be best, but the monitoring would be odd. Initially, I thought I'd play the mp3 on my phone and use some kind of video software on the laptop with the Scarlett as the microphone input. I have Windows 10 and a Scarlett interface. I'm trying to figure out the best way to do it. Then I send it to the Mac/Logic guy who figures out how to put it together into a split screen video. It's supposed to be a lossless format like wav. They want the audio better than the usual phone audio. Apparently, I'm supposed to listen to an mp3 and record a guitar track with video. So, to get started, one guy send around some mp3s and charts. Each one shows a different musician and we're all playing the same song. The idea is to post a video with the screen divided into 5 sections. Some friends and I decided to make one of those split screen videos.

Vsdc split screen