1) It depends on gear. However from 3 possible choices of arcane/frost, fire, or arcane, i think standard fire spec is the best (and easiest) overall (boss, aoe, heroics). You can google exact talents but its hard to mess that up.
2) Google, there are many good guides available
3) Yep, troll.
4) They are not complicated at all, i recommend just watch some kills on youtube, or try to find old arcticles about strats on google.
"Pyromaniac" or "Playing with Fire".. idk, i really don't like talents what gives 1% per point. i exchanged it to Clearcasting and Icy Veins.
i made this build, because in early game i think i will got mana issues (or i just overstimate this? i have Evocation and mana gems+mana pot).
At this point, bosses die slow due to everyone being bad geared, so i would not take Icy veins, but 3% dps increase instead. Also DB and Blast wave is immensely useful on kara/heroic trash.
If you have too much mana, you can always just not use evo, or instead of mana pot use destro pot, or use molten armor. So you can convert mana into dps.
But if you ever run OOM with evo and stones/pots you are ****ED and its a huge dps loss to invis drink.