The only way things like this will work perfectly is that a new standard is made for all chars:
SysVar(3) is unused now, right? well, let's have it set to 0 always when in self state
[State -3, Custom State]
type = VarSet
trigger1 = 1
SysVar(3) = 0
then you just add this to all your throws in which you use ChangeAnim2:
[State xx, ChangeAnim2]
type = VarSet ;var set in a custom state yeah
trigger1 = 1
SysVar(3) = Anim
the only var set allowed in custom states
Now you can check for SysVar(3) in state -2 and modify whatever is needed.
I'm not saying this is practical, but if it had been standard when elecbyte created MUGEN