RE: how important is it to match pinion gear pitch?
Just to throw something into this discussion, the term "pitch" on the gears refers to the number of teeth per inch, as in a 48 pitch gear if it was flat would have 48 teeth per inch. With that being said, 32 pitch will never work with 48 pitch.
As far as manufacturers, if it is a 48 pitch it will work with other companies 48 pitch. I use Robinson, Losi and Kimbrough gears and they work together just fine!!