MLM w/ MEG - Dual Mono Outputs, Buffer, etc.

I would like to use a mini line mixer with a mini effect gizmo to switch 2 delays and a reverb in parallel.

If I want the final output of my pedal rig to go to 2 amps, can I just use the L and R to go to both amps in dual mono (no stereo fx)...if this is possible, any grounding or phasing issues I should worry about?

Lastly, since it's part of a guitar rig in front of the amp, and not in the fx loop, is it essential for me to plug into the input buffer and/or click stopper on the MEG before the MLM?