brake switch query - tying into GT500 ABS

[jab351w]

my question is if there needs to be a pedal switch - can I use the existing FFR switch?

the FFR RF Brake Switch has two sets of pins, the "brake switch" pins are closest to the pedal, and is normally closed - and when you push on the pedal the switch opens and turns on the brake lights

It's the other way around: for the brake lights the switch is normally-open and closes when the brake pedal is depressed. Based upon the highlighted portion of the schematic, the ABS module wants the opposite to happen: the switch should be closed when the brakes aren't depressed (12V to module) and open when they are (open circuit to module). If your brake switch has both normally-open and normally-closed contacts, you can connect the NC contacts to the ABS module and the NO contacts to the brake lights, with +12V feeding both. Assuming the 12V source feeding the switch is hot all the time this means that the ABS module will see 12V all of the time when the pedal isn't depressed, even when the key is off. This differs from the OEM application shown in the schematic where the 12V feed is switched by the PCM power relay. This may or may not cause the ABS module to remain active all of the time and increase its standby draw on the battery. If it does you could add a relay that's activated in start/run to replicate the function of the PCM power relay and feed the NC brake light switch via that.

I believe the clutch switch portion is normally open, and when the pedal is pushed - it connects the signal (is this a correct assumption?)
here's what I need for the GT500 ABS config, see yellow highlight below

You can verify operation of both sets of contacts with an ohm meter or test light. If you have continuity through the contacts when the switch isn't activated and no continuity when it is, then the contacts are normally-closed, if the opposite then they're normally-open.

trying to understand the power circuit with relay at the top of the GT500 wiring diagram
if 86/87 are HaaT, and 30 is the switch to turn on 87 which will transfer power from the 85 (PCM) /86 connection?

Yes, 86/87 on the relay are hot all the time. The PCM grounds the relay coil (85) to close the contacts and connect 87 to 30, feeding +12V to the brake switch.