Any type of lubricant that is NOT petroleum-based will work. Vaseline, etc, will eventually deteriorate the latex-rubber, which is why KY is recommended for ... ummm...
Silicone is a DEFINITE NO-NO. It has a tendancy to eventually get everywhere, and will guarantee to cause the glue never to stick if you need to make repairs or ever replace the zipper.
You can also use any non-scented-type of talcum powder to sprinkle on the seals (no, not the barking ones!) before insertion (heh-heh-heh). The standard kind, like J&J Baby Powder (can I mention brand-names here?) is scented, so it's a no-no. Ask the druggist for suggestions, or have them point you towards the unscented kind (if you can still look him/her in the eye after reading all the small-print on the 'personal lubricant' tubes by this time).
I'd imagine the hair conditioner you mentioned is scented (most scents are petro-based), so it probably isn't a good idea. Probably not too good on a wetsuit either in the long-run, come to think of it (but hey, you got a drysuit now, so who cares?).
Seal-trimming (Hey! We've already been thru this part, ok?) should have been covered in your drysuit-course. You DID take one didn't you?
Steven Barsky has a great book out, and it's aptly named..... (drum-roll).... "Drysuit Diving" (to be fair there may be more, I just happen to use/teach out of this one). Pick one up at your LDS, and quick!
Oh, and one last thing. Remember: You can pee in your mask and spit in your wetsuit, but don't do either in your DRYsuit (that's why that named it that, silly!).
