I don't have the compact from CZ but I have a matte stainless 75B that's been a nearly perfect pistol and I can answer most of your questions.
If this is the one you're asking about:
CZ 75 COMPACT
I think the safety is right hand only on this model.
Yes, night sights are available for this pistol, but I don't think it can be ordered with them already installed.
Yes, it is DA/SA.
The model above is not a de-cocker, The model linked below is a de-cocker, has the same mag capacity and is only 1.7-lbs. The CZ P01 and CZ P06 are also de-cockers, the P06 is only listed in 40 S&W.
CZ 75 D PCR COMPACT
Mags, grips and holsters are available for some of the CZ pistols, but I'm not sure how easy they are to find in your area. Most of them can be found online though, CZ USA has a site for parts and accessories and there is also CZ Custom. Holsters for other compacts will fit too, but I'm not sure which ones specifically, CZ USA does have a forum that can also help with locating these items.
The CZ USA contact page has an e-mail address and they should be able to answer any questions a little better than me.
CZ USA contact page.
Also, I'm 100% sure about the compacts, but the full size 75B's in satin nickel have blue or black controls, safety, hammer etc..