AE is already integrated, so you can control it using "Settings & Tools".
On the other hand I don't know wheter you can set it up to use Heirlooms. It will propably exchange heirlooms with "better" gear (I remember reading about such a bug? don't know, you may try), so you might want to equip heirlooms and completely disable AutoEquip (as you don't need to equip anything).
As for the other thing: Ofcourse it can start a Level 13 Toon.
You have two (major) methods of leveling: Questing (as for that I recommend "Kick's 1-90 Leveling Profiles", they do a good job to me)
Dungeoning (just select Dungeonbuddy and go to Bot Config -> Dungeon -> Random Dungeon (BC, WOTLK, CATA...)) Warning: Some people say, that you should never ever go with a group of random people. I do, the toon is now 81 and the account alive.
You can also do Battlegrounds or Grind, for Grinding I don't know a good profile and BGs shouldn't require some profiles at all (do BGs still give that insane exp amount?)
Edit: You have to go to Honorbuddy -> Profiles -> Questing (or something, just look under Honorbuddy and then Profiles)