egg beater ?
 

I recently put crank bros candy C's on my new WW trike. It is a lot easier to clip in now and it might eliviate some of my hot foot/toes

can I use the crank bro's cleats on my old clipless pedals (forgot to try) or do I have to switch all my pedals to eggbeaters now?

Crankbrother cleats only work with crankbrother pedals from what i know so yes you'll either have to switch all your bikes to CB pedals or you could get a second pair of shoes to use with your other pedals (which may be cheaper than picking up 2 or more sets of pedals).

Doesn't Crank Bros. make eggbeaters too? The cleats should be the same for the eggbeaters, candy c's, etc.

Yes, all Crank Bros. pedals can use the same small cleat. I have egg beaters, Candy and Quatros and use one pair of MTB shoes for all.

Crankbrothers cleats will not work correctly with SPD pedals if that's what you're asking.

I cheat and use the SPDs cleats (and MKS cleats, too) with my eggbeaters, and they seem to work. They aren't as snug as with a SPD pedal, but not overly tight (more loose, really), which I can live with. I suggest you try them out with SPD cleats before you go and buy a pile of new pedals. It would be cheaper to buy an extra pair of shoes if the SPD didn't work.