Leveling 80 - 90

[MiRai]

Just some quick general answers to get you started...

a) Is it best to instance? or Quest?

What's "best" is what you find more appealing so that you don't get burned out; but which do you enjoy more: The monotonous scenery of instances over and over and over again, or the outside world where you can breathe fresh air?

Most people mix it up.

b) Is a hunter the best thing to boost with? (Probably no, thus what is?)

Any class/spec that does burst AoE damage and can either soak up incoming damage or kill fast enough to avoid it.

c) What is the best build to boost with?

I realize you're asking about your Hunter, but I answered this above.

e) Do I just do 5 man questing and level all of my accounts at the same time rather than pulling them up with my 90?

This question sounds like your first one... just rephrased.

f) Once this team hits 90, which of the classes do I want to use to pull the rest of them up?

Any class/spec that does burst AoE damage.

[deathjester]

This question sounds like your first one... just rephrased.

Sorry, I didn't phrase that correctly. I meant to sayo I use a level 90 to boost with, or just quest with 5 level 80's?

[suicidesspyder]

Sorry, I didn't phrase that correctly. I meant to sayo I use a level 90 to boost with, or just quest with 5 level 80's?

If your going to quest 5 level 80s so they are on the same quest line.
If in an instance swap out a lower for your boosting toon.... Although, If you can tank dps and heal using your 80s use that team. Like stated above aoe damage is the best also yes mixed it up i quested my first team no dungeons boy collection quests got old.
Next set i mixed it up so much better.