Wait what JOJO characters are you talking about(I thought you were talking about the megaman ones)
...if you're talking about some others I am sorry I wasn't of any help... weep
Yep, the megaman ones.
I just found out how to do the specials. Press D,DF,F, a+b+c when you have very low health or when it shows that mask/start near you life gauge. I also found out if you hold start while selecting model z he has stronger, cheaper moves