So you have
Account 1.70 Druid Tank
Account 2.70 Priest in S1 & Shadow gear
and 3 more new accounts?
Account 3
Account 4

Account 5


I like the idea of creating "alts" in each account that does different thing then my main. And each character would have a Primary role, and Secondary role (tank, healer, dps).

So, Account 1 have a Druid tank 1st, and Healer / Boomkin, 2nd. I'd roll a DPS caster class like a mage/warlock.

Account 2, Priest is DPS 1st, and healer 2nd. I'd consider rolling a tank in this spot, but not yet since you have 3 other accounts. I'd stick with a DPS spell caster class like a mage/warlock.

That leaves 3 accounts.
Account3.Tank
Account4.Healer
Account5.DPS

Level 1 to 12, quest.

At level 10, get the quests for Rage Fire Chasm (1 in UC, 2 in Orim, 2 in TB).
Also, doing class quest help you gain some exp while helping each toon.

I would keep these 5 quests in one character and not turn in (A Mage would be great) (why? 4 of the quest are shareable, and in the future twinks/alts, you can share them and have your Mage to complete the quest without traveling to the other cities at the time, and giving them a port there after).

I would use your Account1.Druid to clear RFC with Account 2 to 5.

Then I'd reset and clear the instance again, leaving the objective mobs alone.
Log out the Druid and login the S Priest, kill the objective with the Account1.DPS (Even with Account 3-5 leaching some exp) .

From 14 on out, until you get quests for Wailing Caverns; then repeat with Druid & Shadow Priest to get Account1.DPS get his instance quests complete.