Well to be honest, Strider was never really a problem when it came to rights-- it was more the fact that they didn't incorporate him into vanilla MvC3 the way they wanted to and had to push the deadline corporate set. From what I've read in multiple places, Moto K never had a problem sharing the rights and IP of Strider with Capcom. They just used the entire rights thing as BS fodder after the fandom got out of control.
The rights to Karin would be with Masahiko Nakahira & Shueisha (those peeps who own Shounen Jump). I doubt it would be such a big problem to get the rights for her as long as they did it beforehand.
Ono however said Dan is impossible, simply because he was killed in the storyline opener, lol. However, I still believe anything is possible within the inner realm of Capcom made Street Fighter characters. No one outside of Marvel and Arika would give Capcom much shit in character rights, especially manga people.
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