Yeah, that pocked guide is the one I mentioned, but I'm still not sure where he got his info about these items. The Kadala thingy also says Hellcats are from lvl 15 :-D But I guess it's tested.
Check out the post by fst
he posted a level 1 gambling sheet.
don't think you can gamble anything else for DH at low level. But you can always check out this kadala thingy, dunno how exact it is though. just tested the hellcast waistguard, works fine on level 1 DH.
But, since there's still a week left before season 12, you can just test those things. get some shards, make a new char and gamble away