A few things...
Sableye is going to need at least one attacking move. Having nothing but status moves makes it Taunt bait. I say go for one of two options:
Sableye
Item: Leftovers
Nature: Bold
[EV's: 252 Def./ 252 Hp/ 4 Spe.]
Ability: Prankster
- Taunt
- Recover
- Will-O-Wisp
- Foul Play/Night Shade
Foul Play uses the opponent's Attack stat to calculate damage, so it's a good counter to powerful Pokemon, but Night Shade is more reliable and does a fixed amount of damage, so that's up to you which one you prefer. Also, I replaced Confuse Ray because in my opinion it's the least reliable of your four moves. Confusion isn't that good because the target can just switch out of it. But if you'd rather replace another move that's up to you. Bottom line, you need an attack move, and Foul Play and Night Shade are the best options because they don't rely on Sableye's Attack stat (which isn't that good).
Shuckle's best features are a bit wasted on your Shuckle set. Mainly, it doesn't take advantage of Shuckle's enormous defenses which let it stall out an opponent while it takes residual damage. Replace Knock Off with Toxic. Shuckle's Attack stat is basically non-existent, so attacking moves are useless on it. Making your opponent lose its item is nice, but after you've done that you'll have no way of inflicting damage. Also, Sturdy as an ability would be more useful, because your moveset doesn't take advantage of it (which would generally be done with Curse to boost Speed). Finally, in order to take advantage of its bulk, give it a Leftovers instead.
Shuckle
Item:
Leftovers
Nature: Relaxed
[Ev's: 252 Def./ 252 Sp.Def/ 4 Hp]
Ability:
Sturdy
- Gastro Acid
- Sticky Web
- Stealth Rock
- Toxic
For Blissey, I wouldn't go with Attract. It's just not reliable. Since it's based on gender, it'll only work half the time (actually less than half when you take genderless Pokes into account). For a more reliable way to cripple your opponent, go with Thunder Wave instead. Also, you should invest more EV's in Defense instead of Sp. Def, otherwise Blissey risks getting OHKO'd by a type neutral physical attack. It doesn't need any investment in Attack because Seismic Toss doesn't use it.
Blissey
Item: Leftovers
Nature: Careful
[Ev's: 252 Def/ 252 Hp/ 4 Sp Def.]
Ability: Natural Cure
- Heal Bell
- Thunder Wave
- Wish
- Seismic Toss
I won't say anything about the Luxray since it sounds like that's the one you want to keep, but I would say you should be open minded to replacing Magnet Rise if you find yourself having trouble with this set. Getting immunity to Ground moves is good, but the moveslot might be better used with something else--
Knock Off would be my move of choice.
Hope this helps!