Heatran should be using Leftovers as the item; considering that it will be passively taking damage from the hail Abomasnow brings, it helps to cancel the passive damage. To reduce the amount of damage Heatran takes from Stealth Rock, use 248 HP/252 SDef/8 Spe.
Alakazam is better off using Focus Blast over Grass Knot so that it can hit Tyranitar harder than Grass Knot would.
What's the point of using Lonely on Kyurem-B if you're not investing in Attack?:
-Substitute
-Dragon Claw/Blizzard
-Fusion Bolt
-Blizzard/Roost/Hidden Power (Fire)
Nature: Lonely/Adaman
EVs: 56 HP/216 Atk/236 Spe
Item: Leftovers
or
-Substitute
-Dragon Tail
-Roost
-Hone Claws/Blizzard
Nature: Careful/Sassy
EVs: 252 HP/64 Def/136 SDef/56 Spe
Item: Leftovers
Rain Dish is still the preferred ability on Tentacruel so it can mooch off of any potential perms-rain that Politoed brings.
I am using Air Balloon on Heatran so he can avoid upcoming earthquakes or ground moves in general
And i am running mix on kyurem thats why lonely so i wont have to invest anything on atk