As much as I love to hear you fellows argue about Sponge Bob, I think it's best if you do so else-where.
Now, if anything, I would consider Mario a Donkey Kong character. Mario took his big break from Donkey Kong's game, after all.
I do not mind the parallels of the two series, as they're closely intertwined. However, Cranky Kong IS the original Donkey Kong. I don't care to debate it with any of you, however. Believe what you wish.
But no, I wouldn't consider Donkey Kong a Mario character. Not in a heartbeat.