Sorry, Kevin and moskus, but I can't be of much help here.
The inputs labeled Multichannel seem to be specific to using WDM drivers (at least I've never seen them using MME drivers). I believe it has something to do with using more than one Delta card in the same system - something Delta calls multiclient, I think.
IOW, having 2 Delta 1010's so you can get 16 inputs.
,
Delta used to label some of their drivers as "multiclient" drivers, and that's where I have come across this before. As such, I was going to suggest using a "non multiclient" driver version. But in peeking at their site, I don't see where they make this distinction anymore.
Obviosly the workaround is simply input/outputs that work. But I can see where this would be a minor nuisance.
Anyway, that's the full extent of my knowledge on the subject.
As for the other problem, even though M-Audio uses the same drivers across the entire Delta line, you should still only see the number of in/outs that your card actually has physically. (Remember SPDIF is an input/output as well.) Why you might see more than you actually have is a mystery to me.
What OS are you using? I might try a different driver version to see what happens.