The “different” signal path between XLR and Jacks is a set of damping resistors to reduce the line level to something acceptable for the wide-gain mic preamp. Maybe we’re talking about some external preamp????
Yes, but are the stereo line ins having mic pre gain? I think not, but looking right now. There is a trim control; but no mic preamp… on the ST inputs. Same knob, different function.
to settle
In actual fact if you use the Mic input.
You can get a weak signal from the line output.
What you would use that signal for I have no idea.
Its all in the box these days.