First, testing in the arena doesn't always work. The arena messes with creatures' morale, emotions, and loyalty, so syndromes that affect these probably won't work as intended. Adventure Mode is best for that kind of testing - make a creature that uses your interactions naturally, then give them [OUTSIDER_CONTROLLABLE] (or whatever the tag is) and make an adventurer of one.
There's a couple errors in BLOOD_CRAZE:
1) [IE_ARENA_NAME] should go under [I_EFFECT], not [I_TARGET]. Not sure if that's really serious or not.
2) CE_FEEL_EMOTION should look like this: [CE_FEEL_EMOTION:EMOTION:RAGE:SEV:10000 <etc>]. You've dropped the extra EMOTION and included a string "rage" which isn't called for.
3) Not really an "error," but try setting START:0 for all of these (instead of 1) - should make it happen sooner.
PROPEL_UNIT actually requires two targets. SAVAGE_KICK should look like this:
[INTERACTION:SAVAGE_KICK]
[I_TARGET:A:LOCATION]
[IT_LOCATION:CONTEXT_LOCATION]
[I_TARGET:B:CREATURE]
[IT_LOCATION:CONTEXT_CREATURE]
[IT_MANUAL_INPUT:target]
[I_EFFECT:PROPEL_UNIT]
[IE_PROPEL_FORCE:100000]
[IE_TARGET:A]
[IE_TARGET:B]
[IE_IMMEDIATE]
and the corresponding creature entry:
[CAN_DO_INTERACTION:SAVAGE_KICK]
[CDI:ADV_NAME:Savage kick]
[CDI:TARGET:B:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:B:2]
[CDI:USAGE_HINT:ATTACK]
[CDI:FREE_ACTION]
[CDI:VERB:unleash a powerful kick:unleashes a powerful kick:NA]
[CDI:MAX_TARGET_NUMBER:B:1]
[CDI:WAIT_PERIOD:100]
Target A is, I think, the point away from which target B (the victim) will be propelled. Since you can't manually select it, it will always be the location of the interaction user - hence, the interaction propels target B away from the user.
I suspect trying to make SAVAGE_KICK work on an actual kick is fruitless. The SPECIALATTACK_INTERACTION tag is used for default werebeasts and seems tailored specifically to their bite-curse-transfer mechanism. It's probably an issue with the multiple targets that PROPEL_UNIT takes.