For Tentacruel, Scald is a better option over Hydro Pump because its current set is a support set; Scald has utility in possibly burning opponents and Hydro Pump's low PP can easily be stalled out.
Also, Kyurem gained Earth Power to deal with Heatran more easily as well as Roost for recovery in B2/W2, so you can consider those moves.
If Abomasnow is using a Calm nature, Wood Hammer isn't advised because it runs off of the lowered Attack stat that Calm would have caused. Substitute is the best option in the last slot because it works well in tandem with Leech Seed. Leftovers should be the item to use.
Okay, I fixed it. I added their EVs, and Tentacruel learned Scald. But I forgot about Abomasnow, I'll do that later. I dont have b2/w2 so I have no way of teaching Kyurem those moves.
I thought about Mamoswine, but I would have to teach him TM stealth rock on 4th Gen, but I can't do that. So I decided not to do that for now. Also, same deal with Scizor and Superpower, it's a tutor move on 4th gen (I believe). But Walrein is so good! You Toxic, then take small damage. Use Substitute, and if you lose it, who cares? You have Ice Body and Leftovers. After one protect, he's completely healed from substitute. If he still has his substitute, use blizzard. It's 100% accurate in hail.