I’d suggest using a Group Track. Send the Loop Mash Instrument track to a Group, then, send the Group Output to the Input of the Audio track and record. This way your Stereo Bus is not hindered. In addition, you could route other tracks to that same group if you wanted to sub-mix two sources, like the Loop Mash and the other one. As far as recording the performance controls, that’s with a MIDI Track using Loop Mash FX, similar to how the Midi Gate works.
P.S. – Just back to add that you can also use Render In Place on Loop Mash, and, if you have recorded a MIDI track to trigger the Performance controls or the transport functions of Loop Mash, those will also be included in the rendered track.