Try goggling hand stretching. You may find a video online and it will save you buying a new hand. You should only need a few thousands. All you need is a punch,hard surface and a hammer.
I do bluing with Dicropan "IM" from brownells and have had good results with it. I was thinking of oxynate 7 but it takes 4 tanks instead of 3 and you cant use it on doubles or anything with silver inlays without messing up something. It takes a little longer with Dicropan but the results look...
I load the 5.7 and the only problem I have is collapsing the neck when resizing or seating the bullet. Other than that you have to have a small hole funnel so you dont scatter the powder trying to get it in the small short case. I wait till I have a bunch so I only have to do it every six...
Any good gunsmithing shop should be able to reblue and do a good job. Prep is secret to a good blue job.I like the slow rust blueing, it takes longer but it looks better.
Look at the bottom of the flashhider and see if you dont see a pin. if it was done right it will be hard to see . What size is your barrel? if its less than 16 without the flashhider its pinned and you will have to grind some to get it out.
I installed the FSS kit in a customer's gun a few weeks back and it took the trigger pull from 7lbs down to 3 with a shorter reset and smoother pull. He loved it. No sure about the other one. I got my kit from Brownells.
I bet your existing one is pined or welded on. Look close on the bottom of the break and see if you dont see signs of a pin being covered over. If so you will have to grind or cut in to it to get the pin out. You may be lucky and it not be but dont bend your barrel trying to force it off.