You're not doing yourself any favours with Blizzard Mamoswine. You can get Icicle Crash instead. I'm also surprised you don't have Ice Shard, it's almost a must on something that's neither terribly fast nor very bulky. And for the 4th move (keep EQ), you can also breed Body Slam; it's high para rate goes very well with IC's high flinch rate.
I assume you went with that because of Empoleon's bad level-up pool? Cause I'd definitely recommend you get Ice Beam, Grass Knot and Agility, makes it an actually very efficient sweeper. Grass Knot is there because only Water types resist both Water and Ice. To get Ice Beam, you need to go back to an episode tgat has the old breeding mechanics. The pinned guide in this section has a link to one of those, as well as detailed explanations of everything you may need and ways to greatly speed up the whole process, even the specific chain for Agility and Ice Beam is listed (Grass Knot being a TM in the game). Feel free to send me a PM if you need any help.
Your team is a ton of hard hitters. Compared to what they can do in one hit, T-Spijes damage is next to nothing. Drapion is also a physical attacker, no need for Dark Pulse, give it Night Slash instead. Also, pre-E13 gets you Swords Dance and either Dig or Agility, depending on which you'd prefer: Dig helps out your coverage a bit while Agility makes a sweep much easier, since Drapion's speed could be better. Just send it out against a physical attacker and setting up one of each SD and Agility should be no big issueost of the time.
Ditch Crunch, Pyroar's physical attack is bad. You could give it Dark Pulse instead. Also, Endeavor isn't the best thing ever to use on something with Pyroar's "defenses". Give it Hyper Voice for a secondary STAB instead.
I'd reeeeally recommend ditching Meowstic, it's far outlived it's usefulness at that point. Want me to think of some options to replace it? Cause there's plenty that would do better.
Dotch Giga Drain and Grass Pledge, Torterra is a physical attacker and you don't have a way to utilize the pledges' effect anyways. I'd say give it Wood Hammer and either Curse or Superpower. Torterra does very well with a Curse set. Another option is making it's 4th move Rock Polish, though it's not as efficient as Curse.