Yes, the safety will come with the detent and spring.
It does not exactly match the standard Magpul Flat Dark Earth. It's darker
Yes, this should be compatible.
Any standard AR safety selector should work in the lower of the MPX.
The safety selector should be correct, but please be aware that because the lower is polymer, the fit may not be perfect as it is not a true mil-spec lower receiver.
Yes, you can use this safety in a standard AR-10 lower receiver.
Yes, you can use this safety in a standard AR-10 lower receiver.
Compatibility cannot be guaranteed and one of the levers is shorter than the other. The Seekins Safety Selector is one of the only selectors that is specifically listed as being compatible with the Ruger Precision.
Yes, this will work work any of the Timney AR triggers.
It is steel.