1) If I want to run Dual Screen Deoxys-S should I use Reflect/Light Screen/SR/Shadow Ball?

2) If I want to lead with Dual Screen Mewtwo, should I use Reflect/Light Screen/Taunt/Shadow Ball with Lum Berry?

3) What move is more important for sweeping Mewtwo in general-Thunder or Shadow Ball?

4) Should the WOW/StallTwo sets use an attacking move, and if so, which one?

5) Is Agiligross effective in Ubers?

How come Psychic is bad? Electric hits only two types SE and is immuned by one, and I see unSTABed TBs/Thunder everywhere...

Yes. It hits 4 types SE and hits much of OU SE as well. It's probably the best non-STAB attacking type for Grounds as well.

Is Rock a good attacking type?

Rock Slide can be used to OHKO offensive Salamence and Gyarados after Stealth Rock and hit Zapdos just as hard as Ice Punch so I don't see why not. The Flinch rate could come in handy, too.

Among the several AgiliGross clones I'll get, should Rock Slide be in too?

*one

I have an idea-I'll do the same thing when I couldn't decide what last move to give SDLuke-I'll clone three Metagrosses, give on Zen Headbutt, one Ice Punch and one T-punch :P...

Personally, what would you use?
Also, is Agility a real Psychic move? Metagross is a secondary Psychic and gets it, Deoxys also gets it and is Psychic, but also quite a few non-Psychics...then again, Suicune and Kyogre naturally learn Calm Mind, and Ariados Psychic, and both are still the most known Psychic-type moves...your opinion?

Like I said before in a previous post (I'm not sure if it was responding to you or someone else) Ice Punch can OHKO Gliscor and is your best attack against Zapdos. It's also your best attack if you plan on Baton Passing +2 Attack and Speed to it. It's probably best used on the Choice Scarf set where you can outspeed Salamence and Latias and hit them hard but it's still viable on the other sets.

What about Ice Punch? Should it be used?