1. I need to know what would be the correct natures/movesets/EV training that I would use for

Porygon (the last form probably)
Scizor
Rampardos
Umbreon
Lucario

2. and What kind of Poke'mon would I fight to get the Specific EV's?

Like what Poke'mon do I fight for Speed, Attack (ETC.)

3. Can I reobtain items that are used to evolve poke'mon? Such as Metal Coat and Up-Grade?

4. What are these items? What do they do?

Premier Ball
Tiny/Big Mushroom
Oval Stone
Reaper Cloth
Magmarizer
Protector
Dawn Stone
Shiny Stone
Dusk Stone
Odd Keystone
Full Incense
Dubious Disc

Thanks

1. Try this site: http://www.smogon.com/ It has movesets for every fully evolved pokemon if you look at the Strategy Pokedex.

2. Psypoke has that list here: http://www.psypokes.com/dex/search.php?type=effort

3. If you mean after being used for evolution, you cannot.

4. Premier Ball- Same capture rate as Pokeball, just looks different.
Tiny/Big Mushroom- I think that they're useless, not sure though.
Oval Stone- Evolves Happiny into Chansey in the daytime.
Reaper Cloth- Evolves Dusclops into Dusknoir if Dusclops is traded while holding it.
Magmarizer- Evolves Magmar into Magmortar with the Reaper Cloth's method.
Protector- Evolves Rhydon into Rhyperior with the Reaper Cloth's method.
Dawn Stone- Evolves male Kirlia into Gallade and female Snorunt into Froslass.
Shiny Stone- Evolves Togetic into Togekiss and Roselia into Roserade.
Dusk Stone- Evolves Murkrow into Honchkrow and Misdreavus into Mismagius.
Odd Keystone- Used to catch Spiritomb at the Hallowed Tower on Rt. 209 after talking to (I think)32 people underground, or one person 32 times, etc.
Full Incense- When bred, allows Munchlax to hatch from a Snorlax's Egg.
Dubious Disc- Evolves Porygon2 into Porygon-Z with the Reaper Cloth's method.