My personal opinion...

If the string needs changing, do it. If not, wait until it does.
I like the Muzzy Zero Effect rest. WB would be my 2nd choice.
As far as sights, release, stab, etc....most all of that stuff is personal preference. I don't use a stab on my hunting bows. IMO it's not really neccessary. Your shots are relatively close, and IMO it just adds extra weight to the bow that I don't need.
Broadheads, I like fixed heads...Magnus is my 1st choice. Muzzy are excellent too.

The main thing you need to do is make sure the bow fits you properly, and that you get the bow set up correctly, and thatyour arrows are spined correctly with the brooadheads on straight.That is much more important than the accesories you get. Good luck