You should read site of Sakir before asking any question, but, because I'm in good mood today, I will answer.
Yes you can use every character that you use in Mugen.
"If our lives are indeed the sum total of the choices we've made, then we cannot change who we are. But with every new choice we're given, we can change who we're going to be." The Outer Limits S04E04
"If knowledge is power and power corrupts... how will human kind ever survive?" The Outer Limits S04E16