I like where you're taking this. You got the "pipe" sound in there, which is a good thing. Arvis felt those parts sounded a bit like percussion, which I reckon is because the reverb on them sound quite metallic right now. Maybe the sound in the moan wav can also be mixed a little more fluently? Right now, the exhale comes quite noticeably after the sound, even though the sound is clearly made by (more forceful) exhaling.
For reference, and because I'm a terribly lazy man, I'm posting an IRC log here. Not all of it is directly relevant, but it might give you some inspiration. Or maybe a laugh or two.
[20:33] <@Adanorcil> Rats is getting it I think
[20:33] <@Adanorcil> I'm liking where's taken the new hoom sounds
[20:34] <@arvisrend|> though i'm confused by the weird percussions at the end of the sounds
[20:35] <Why|> I'm still longing to hear some more bestial steam horns tbh
[20:35] <@Adanorcil> yeah, some more would definitely be good
[20:35] <@Adanorcil> and the reverb is a little too metallic maybe
[20:35] <Why|> a la http://www.youtube.com/watch?v=jA_WyHHvwCw
[20:35] <Why|> but bestial
[20:35] <Why|> :p
[20:35] <@Adanorcil> more organic sounding, yeah
[20:35] <@arvisrend|> i mean, what's that thing at 0:02-0:04 of exhale?
[20:36] <@Adanorcil> clearly the pipes
[20:36] <@Adanorcil> imagine blowing air through a big pipe
[20:37] <@Adanorcil> Why, maybe we should leave the big resounding hoom sounds for regional effects, though?
[20:37] <@Adanorcil> I think it might be easier
[20:37] <@arvisrend|> sounds like a drum to me
[20:37] <Why|> yeah probably
[20:37] <Why|> though I'd love to hear it go wild when attacking
[20:37] <@Adanorcil> I think it might be hard to do that sound while also having a distinct source nearby
[20:38] <@Adanorcil> without blowing your eardrums anyway
[20:38] <@Adanorcil> yeah, for attacks definitely
[20:46] <Why|> but I'm imagining an angry hoom running up to you, constantly exhaling steamy wet air and making a hell of a lot of noise
[20:46] <Why|> like an old steam locomotive ready to trample you
idles would actually be them sounding off
[20:47] <Why|> I still like the melody playing idea
[20:47] <Why|> for mating season
[20:47] <@Adanorcil> of course
[20:47] <Why|> :p
[20:47] <@Adanorcil> they makes tunes
[20:47] <+Cat> The Dunmer totally train them to play tunes
[20:48] <Why|> I showed it to my sister, who studies biology, and she was all in favor of tunes, too
[20:48] <+Cat> I'm just wondering how they'd modulate the pitch of the note
[20:48] <+Cat> vocal cords down at the bottom of the tubes or something?
[20:49] <@Adanorcil> air flow speed I guess
[20:49] <@Adanorcil> faster you exhale, the higher the pitch
[20:49] <@Adanorcil> relaxed breathing is unhearable
[20:49] <@Adanorcil> same way you don't whistle if you only blow slightly
[20:50] <+Cat> there should be baby hooms that are squeaky and slightly out of tune
[20:50] <~Haplo> that would be very cute, Cat
[20:50] <@Adanorcil> now I'm imagining hoom mating season in the velothis
[20:50] <@Adanorcil> and it sounds like a german brass band
[20:50] <Why|> great
[20:51] <~Haplo> http://www.youtube.com/watch?v=Z7CIHor-wAg
[20:51] <+Cat> what kind of sounds would ladyhooms like best, though
[20:51] <~Haplo> 0:21
[20:51] <+Cat>
[20:52] <@Adanorcil> Cat: the loudest :p
[20:54] <~Haplo> http://www.youtube.com/watch?v=WkkUM6PXrVw I imagine Hooms might have a sound like 0:04
[20:55] <@Adanorcil> Haplo, that's a particularly nasty old male
[20:55] <@Adanorcil> the real strong ones reach the brown note
[20:56] <@Adanorcil> the Dunmer call it "Shit Season"