The hyphen doesn't seem to cause problems, as both castes definitely appear and function properly. They're reproducing, after all. You must have at least two castes, one with the MALE tag and one with the FEMALE tag, to reproduce. We wouldn't acknowledge that there's a problem with babies being ignored in the first place if they never reproduced. Remember that the CASTE tag is just looking for a string by which to identify the caste it is defining, and that string has no other purpose, so there are probably plenty of possibilities that it'll accept. Still, removing the placeholders will save you quite a few keystrokes when selecting the castes in the future, or headaches when you accidentally use FEMALE instead of FEMALE_NORTH for interaction selections.
As for why your little guys are starving to death, I can't say. I know that the mother in the civilizations SHOULD be picking her infant up and packing it around until adulthood, but for the feral sergals... When I install the mod, I remove the BABY tag, because any creature not strictly a member of your working population (able to take jobs, which pets cannot) will not get the job to pick up infants, because they don't take jobs of any sort, and picking up their baby and keeping them alive is a job. So it's impossible to actually breed feral sergals with the BABY tag because they're CAN_LEARN (or was it INTELLIGENT?) and thus need to eat and drink, yet babies can't provide for themselves, usually.
Actually, you have a [LITTERSIZE:x:y] token. Are we sure they aren't giving birth to multiple offspring, picking up one and ignoring the rest? This is a pretty stupid suggestion, and I don't know if this happens with twins in dwarf fortresses, because I've never had a mother give birth to twins in any fortress where I paid any attention to anything, but it's ever-so-slightly conceivable that the game thinks differently about offspring produced under the guise of [MULTIPLE_LITTER_RARE] and [LITTERSIZE:x:y] differently. If the [LITTERSIZE:x:y] tag doesn't flag all of the offspring as needing to be taken care of by the mother, your fuzzy-arsed devils will be acting like eagles and letting the weaker (younger) offspring die. I'd start by testing them without that tag, and maybe inserting the [MULTIPLE_LITTER_RARE] tag. Also observe them more closely when they produce multiple offspring with the littersize tag, and make sure they aren't just picking up one of the offspring
I'm sitting at a computer in my college's lab right now, working under needlessly restrictive operating procedures that involve "don't download or install anything, not even DF.", so I can't do any sort of testing.
[edit]
Damnit, Indigo beat me to it.