WE GOTTA SAVE APRIL: When April would be KO'd by an opposing character's attack, place her on that character's card instead and place a Rescue token on April's card. Friendly characters with the TMNT Ally keyword modify their attack value by +1 when targeting a character that has April on its card. If a character with April on its card due to this effect is KO'd, place April into a square it last occupied on click #1. At the end of the game, the opponent scores 25 points for each Rescue Token on April's card. This ability can't be ignored.

Question
What happens if your own mind control character KO's April?

Rat King from my opponent mind controls my Donatello. Donatello KO's April.
Who gets a Rescue Token?

April would be placed on Donatello's card and the Rescue token on April's card.

So April would come back on the map when Donatello dies but I would get no +1 attack bonus for my characters.

Pretty sneaky.

If only she hadn't rolled her Super Senses!!

And the victory points for rescuing April go to...?

"At the end of the game, the opponent scores 25 points for each Rescue Token on April's card"

You don't get victory points for "rescuing April", your opponents gets victory points for every Rescue token on April's card no matter how they got there.