yes but you may also have to replace the sear and if sear is replaced may have to replace the thumb safety. also depending on hammer possibly have to replace grip safety. might get lucky and have it drop in but I doubt the sear to hammer hooks engagement will be optimal.
don't think so you just eliminate it with a new hammer best of my knowledge, never replaced a hammer on a PT1911?
as mentioned drop in 1911 parts generally don't give you the best setup, fitting is usually needed for that, and certainly safety check the weapon BEFORE using/ carrying it.
OPPS! See OSO ahs already addressed this!
I just replaced the hammer and sear on my SS PT1911 with a Wilson combat set. The only thing you have to do is order a new strut and strut pin, for parts. As for the thumb safety it may need a little work to fit properly. I had to file on mine to clear the sear properly, other than that it works perfectly.