Nope - not really. It's one of the areas that modules from different manufacturers differ. HH65 pedals are easy to find, though and cheap (and won't break down like the FD8!) You may be able to sell the FD8 for the same as an HH65.
May sell a few other items and save up for the RHH135. If I go that route, I don't need the HH65 but I do need a regular Hi Hat stand which I already have. Correct?
Yup. The RHH130 and RHH135 mount on a hi-hat stand. The HH65 is just a pedal and you use that with any pad (note - there are those who say the HH65 has a greater subtlety on virtual hat position and sound than the RHH135... I have 'em all - go and test drive if you have the opportunity)