You will need to purchase mil-spec 0.154" trigger pins for this Triggertech AR-15 Competitive Trigger. I would recommend the RISE Armament Trigger Anti-Walk Pins, found by using the link below:
https://www.opticsplanet.com/rise-armament-rise-trigger-anti-walk-pins-ar-15.html
The Triggertech AR-15 Competitive Trigger will work in Mil-Spec AR15's. So it will work in the M&P Sport 2.
Yes, any of the triggers currently listed on this page will work in a standard Sprinfield Saint Edge lower receiver.
Yes, this is a two-stage trigger. 1st stage: 0.75lbs 2nd stage: 2.75lbs total pull weight: 3.5lbs.
Yes it should be compatible.
Yes, this trigger unit will work with that firearm.
Yes, it should as long as your lower uses standard .154 size trigger pins.
Yes, this trigger should work in any standard AR-15 and AR-10 lower receiver as long as it accepts mil-spec and drop-in trigger units.
Yes, it is recommended to use anti-walk pins for this trigger (and generally any one-piece drop-in trigger).
The Sig MPX uses a slightly different trigger, so it may work with modification. Provided below is a comparable trigger that is designed specifically for use with the Sig MPX and may be a better option:
https://www.opticsplanet.com/timney-sig-mpx-2-stage-curved-shoe-trigger.html