If so, on what occasion, and did they ever play music together?
I think so, I’m trying to remember where and when but I would think the Grammies at least. Try IMDB search for both actors.
From http://www.swingmusic.net/Ray_Charles_Biography.html
Jim
_Ava
4
Probably not what you’re looking for, but they both participated in We Are The World.
That was the one I was trying to remember. They both sang on the Christmas song from this.
Did Ray Charles ever meet Stevie Wonder?
There’s a really tasteless joke in there somewhere, but I haven’t quite figured it out… 
Assuming that the question was answered. I want to add this link.
WWWF GRUDGE MATCH: Stevie Wonder vs. Ray Charles
Enjoy,
Jim
A really tasteless sightless joke in there.
Straight to Hell for that one.
Obviously: No. They just couldn’t see eye-to-eye about it.
Crap! Exactly the “Go To Hell Free” card I was going to play!
Throw in Jose Feliciano, and it practically writes itself.
Zeldar
12
Ronnie Milsap would make it a quartet.
Andre Botticelli for a quintet
I don’t think there is room in this joke for a whole choir
Zeldar
15
What has four legs, a tail, eats oats, and sees equally well out of either end?
Chefguy
16
They wrote the song “Endless Love”, after a three-hour tennis match.
Meeko
17
I thought the obvious “Go to hell free” response was
“how would they know?”
But I can SEE the humor in the other jokes
Ludovic
18
Don’t forget Blind Lemon Lipschitz, who gouged out his eyeballs with a spoon just so he could be called Blind Lemon…it’s true, don’t laugh!
okay, so it’s not
How about yes, but they didn’t recognize each other.
Dammit, you beat me to it. 