1. yes
2. they are not universal, so no the 1911 version does not fit. As to the last part, let's say impractical
3. More than you paid for the Sigma. It's an EDM process, and porting is not the same as a compensator. Both the barrel and slide would have to be ported.
3a You can thread a barrel but you don't have the right one: it has to extend beyond the end of the slide.

IMHO, take two aspirin and lie down until the feeling passes. You have the wrong gun for this project.
Compensators are used on USPSA Open guns built on 1911/2011 frames to allow rapid fire in competition. They are not allowed in other divisions in competition.

If the problem is that you don't like the recoil of a .40 Sigma, the practical solution is to trade it for a 9mm, or load .40 cartridges to minor power for practice..

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Science plus Art