I can't explain this enough, Blastoise does not sweep. Blastoise Walls. So you need a different set and EVs. Here is a Walling set:
Blastoise@ Damp Rock
Calm Nature(-Attack +Sp. Defense)
EVs: 252 HP, 168 Sp Defense, 88 Sp. Defense
- Rain Dance
Here is what I recommend. Rain Dance supports your whole Team, while activating Its Ability Rain Dish. Damp Rock makes it last longer. Scald is STAB, while having 30% chance to Burn is nice. Toxic inflicts Poison while Protect make you Stall. Aqua Ring is an option as well to replace Protect.
Standard Sheer Force Fearligatr. The only thing I can say is replace Crunch with Dragon Dance. Crunch has poor offensive Coverage, and Dragon Dance boosts its Attack and poor Speed.
Okay, I have a suggestion to make your team a little better. Make Swampert your lead, because its probably the bulkiest of the Starters. Here is what I recommend.:
Impish Nature(-Sp. Attack +Defense)
EVs:216 HP, 240 Defense, 56 Sp. Defense
- Stealth Rock
- Ice Punch/Waterfall
Lead Swampert at its best. SR are Roar are obvious. Earthquake is STAB while Ice Punch covers Grass Types. Waterfall is STAB boosted from Rain Dance.
Since its your only Special Sweeper available, I won't recommend anything here.
Same here, can't recommend anything for a Mixed Samurott except to switch the Focus Sash with Life Orb and switch the Nature to Naive or Hasty that raises its Speed.