Why weezing: he is a physical wall, not special. In gen 3 all psychic attacks are counted as special attacks. Thanks to his levitate, there are no weaknesses that can harm him (I assume you're not going to put him out against special attackers/sweepers). Moreover, in gen 3 sludge bomb is considered physical attack (same as all poison attacks), so he hits like a truck with it.
Sceptile is neither a wall, nor a good physical attacker in gen 3 (due to grass type being considered special). There's no need to give him Toxic, because he will die before you manage to stall some significant toxic damage. As I said, in gen 3 Sceptile, if really needed to be used, is better as special attacker. However, in gen 3 there are not so many powerful special grass attacks. Dunno, maybe sunnyday/solarbeam combo? He's fast, so after setting up the sun, you could sweep. Add to that thunder punch (for meh coverage) and... that's all there is in gen 3 for him, because I assume you cannot breed him with crunch.
Keep in mind I give you more of competetive look. In this case you've got pretty poor type coverage. Steel type would help you a lot (swap gardevoir with metagross for more damage/coverage potential and aggron/forretress for tankiness). Umbreon is great special wall with moonlight/protect/toxic/faint attack.
This post was edited by 4funP on Apr 1 2016 10:22am