Is the headmaster that comes with this figure compatible with other headmaster figures? I'm considering using it for and energon scorpion custom but want to be sure it'll work

 

I don't have that PE headmaster, but I do have Warden - his male connector (head) is a bit smaller than the G1 combiner port. It'll fit in fine, but it's more loose (especially since there is only one prong instead of three).

You might be interested in this:
Scorponok Headmaster Adapter Revision by anthony_oster on Shapeways

 

Thanks! I was looking at getting the green king claw kit and using thenshapeways adapter if the one with that kit doesnt work