The total length of the brake is 2.66". If you have a 14.5" barrel, it will take it to the legal 16" requirement if it is pinned and welded. The added length depends on the length of the threads on your barrel. Threads range from .65" to .5" so it will add roughly 2" in length.
Although this may fit, I believe this mount would be too large/heavy for a pistol. This mount is geared towards PCC's.
The Lantac Dragon Muzzle Brake would fit an XDM Elite, however, it will likely require shims to time the muzzle device properly. I would instead recommend the TRYBE Defense Universal Single Port 9mm Compensator, found by using the link below:
https://www.opticsplanet.com/trybe-defense-universal-single-port-9mm-compensator.html
Yes. The Lantac Dragon Muzzle Brake uses 1/2x28 threads and supports calibers with a bullet diameter of 0.358" or less (9mm), and the PSA AKV uses 1/2x28 threads making this muzzle brake compatible.
Yes. The Lantac Dragon Muzzle Brake uses 1/2x28 threads like the 509. Although, this may be slightly large for a handgun. I use the Griffin Micro comp found using the following link:
https://www.opticsplanet.com/griffin-armament-micro-carry-comp-1-2x28.html
Yes it does appear this item will be compatible with your Masterpiece Arms 9mm.
Yes, this muzzle device will fit that firearm.
No, unfortunately the CZ Scorpion Evo S1 uses metric threading, so this muzzle device won't be compatible.
Yes, this muzzle device will fit that firearm.
Yes, it should fit.