Yeah, it would make sense unless a variation was made that applied the lion heads to you feet as well, would be a weird tech lolI believe Mountain Palm is simply unrestricted because it's hard to actually pull off in a fight, great technique but not a super powerful one and a lot of canon jutsu are unrestricted even at S rank when they're not super powerful or useful constantly. As for the twin lion fists, I'm pretty sure the plus twenty applies to any taijutsu period, though I'd probably only use it with hand based taijutsu logically, it wouldn't make much sense to boost kick based taijutsu with them after all.
With that said, that's everything congratulations on completing your training in Gentle Fist!
Thanks man, I appreciate the time you took to train me in this! I finished the Bee Contract and Tech earlier and now I get to try and get Aburame and Senjutsu training if my bio gets approved