Yes, the Geissele Super Dynamic AR-10/AR-15 Enhanced Trigger will reduce your overall trigger pull weight to 2.9 - 3.8 pounds. It is also a two-stage trigger which allows you to know exactly when the firing will take place upon pulling the trigger.
The Geissele Super Dynamic AR-10/AR-15 Enhanced Trigger is not compatible with the Sig MCX Rattler due to the MCX's use of a firing pin safety lock. I would recommend the Triggertech SIG Sauer Adaptable Trigger, which can be found linked below:
https://www.opticsplanet.com/triggertech-sig-sauer-mcx-adaptable-trigger.html
Yes, the Geissele Super Dynamic AR-10/AR-15 Enhanced Trigger includes Milspec trigger and hammer pins.
Yes, the Geissele AR-10/AR-15 Super Dynamic Enhanced (SDE) Trigger will function as intended with a 45 degree selector switch.
The Geissele AR-10/AR-15 Super Dynamic Enhanced (SDE) Trigger is a kit trigger and not a cassette trigger. It will require more assembly in the receiver than just placing the trigger pins in place.
The Geissele Super Dynamic Enhanced Trigger can be used in Mil-Spec dimension AR15's. So you should be able to use it in a .300 Blackout AR pistol. The warranty on the trigger is voided if it is used in Pistol Caliber AR's or the Sig MCX/MPX. However, I recommend contacting Geissele in regards to their warranty to be safe.
The Geissele Super Dynamic Enhanced Trigger will work in Mil-Spec dimension AR lowers. It might work in a DBX57 but I recommend contacting Geissele to confirm compatibility.
According to the manufacturer the Geissele Super Dynamic Enhanced Trigger SD-E or any of their AR triggers are not designed to work in PCC's or with pistol caliber AR variants.
Yes, the Geissele Super Dynamic Enhanced Trigger will work in the Diamondback DB10.
Yes they are both mil-spec (small) pin trigger.