Blastoise-
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
Ability:Rain Dish
Calm Nature(-Attack +Sp. Defense)
EVs: 252 HP, 168 Sp Defense, 88 Sp. Defense
- Rain Dance
- Scald
- Toxic
- Protect
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.
Feraligatr-
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.
Swampert-
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.:
Swampert@ Leftovers
Ability:Torrent
Impish Nature(-Sp. Attack +Defense)
EVs:216 HP, 240 Defense, 56 Sp. Defense
- Stealth Rock
- Roar
- Earthquake
- 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.
Empoleon-
Since its your only Special Sweeper available, I won't recommend anything here.
Samurott-
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.