The 85 Combat does not have the firing pin block system, and as a consequence, has a totally different firing pin group. (It has a stop, rather than a firing pin retention roll pin.)
You can order the needed parts from CZ -- about the only source. They're pretty quick.
I've heard of 75B firing pin retention roll pins breaking, and also about ONE firing pin break. (One.) I've never heard of an 85 Combat breaking in those areas. I've been shooting mine for years -- and except for an early problem with a slightly out of spec slide stop, it has been trouble free.
Get a spare slide stop. That's also unlikely to break, but you can't substitute a 75B stop. Get the firing pin group parts you want, and a couple of recoil springs. And, maybe, a slide stop retention spring. You should be good to go.
(Jim Miossi has a hardened steel sear that should hold its "edge" for many years, and will soon have a hardened stell hammer. Those parts are apparently a bit softer on the standard CZ guns. I've got a Champion sear installed in mine, but don't really know that its really "harder.")