Short answer to your first question is no, not necessarily. Typically, the FPB induces some creep and perhaps stacking, but sometimes even a PreB trigger can exhibit plenty of stacking and grittiness without the firing pin block. I have a transitional and a pre-B that both required a ton of work before the double action trigger got better. And because of the design of the CZ 75 trigger there is creep/travel before the break anyway, which many complain is a problem. However, in both cases, my preB and transitional now have very smooth, trigger in double action and one of them is exceptional. But it took work. I have picked up the type B guns that have had decent triggers out of the box.
Frankly, I don’t think the trigger on the CZ 75 is all that nice in terms of its feel, but all of them can be shot accurately because of the grip and design.
To me the biggest problem in the C 75 system is putting a deCocker on it, which was not designed to do originally. The deCocker generally introduces a ton of grit and stacking into the CZ 75 double action system in such a way that it really inhibits The double action. Most P01s and PCR’s suffer this out-of-the-box problem to a high degree and require a bunch of work and changes. If Cajun gun works was not around I would not own as many at all.
Also, the trigger return spring design is sometimes a problem because of the stresses put on it and you can get some bad ones that will result in broken trigger return springs in what I consider a premature lifespan.