I can only give you one example on holsters.
I bought an IWB holster from White Hat Holsters for my P01 Omega. I had to modify the holster with heat and large common screw driver.
The reason, I think, was the P01 only has the decocker on the left side of the frame. The P01 Omega has the decockers, or safeties (I use safeties) on both sides of the frame. The right side safety was being pushed from SAFE to FIRE position from contact with the kydex. The heat gun and screw driver reformed that spot in the kydex to hold the right side thumb safety in the SAFE position while the gun is in the holster.
As to lights/lasers, there shouldn't be any difference. If you go to the CZ USA website the only thing the description of the P01 and the P01 Omega shows about the rail is, "With an integral accessory rail on its dust cover" The descriptions use the same wording so the rail dimensions are probably the same. I don't have a regular/decocker P01 though.