but the sad fact is that Masquerain's "special attack" (highest stat) is just base 80 or around there... there are much better water types out there. Whatever it can do, Vaporeon CAN do the same, with a better type combo, a better ability, and a much higher stat to do it better.
Grass type- just use eggy instead... exact same strategy
Exeggutor- [sp.atk + / atk -] @ quick claw
EV: Sp.atk and defensive stats, boost Speed EV until speed is 165+
-solarbeam
-sunny day
-HP Fire
-explosion/psychic
as for bug type, it's either Heracross, Armaldo, Scizor or Pinsir. Really you don't have much choice (sadly), and all bugs must go physical too. There's Shuckle but he's... "quite special". Super staller who dies at the sight of any evil egg it sees.