M: Speed Racer. I admit I don't really know him (somehow I missed the memo) but no way I'm marrying either of those other guys.
F: Shaggy. Probably a mistake, but could make for a fun weekend, provided I don't get too stoned.
K: Fred Flinstone. I mean please.

I always thought Speed Racer had a little sugar in his tank, if you know what I mean.

M: Fred. He's a big doofus, but lovable.

F: Speed Racer. The others have zero sex appeal.

K: Shaggy. I know...I hate to hate on the stoner, but he's a horribly annoying stereotype of a bad stoner.

GAAH! What horrific choices. Fred's a raving misogynist, and Speed and Shaggy have always set off my gaydar.

So it would have to be
M/Speed,
F/Fred (a bastard, but straight), and
K/the Shagster.