I am finding it easier to start new and lvl 5 then trying to fit in other later.
You could try

Account 1: Warlock (with the druid/s priest)
2: Warlock
3: Mage
4: Pally
5: Druid/shaman/priest

The reason i say something similar to this is that. If you lvl them up you have a team and you'll learn the macros as you go. You could always at say 70 replace the warlock on account 1 with the druid or s.priest. Along with that you can always respect the pally healing and account 5. to whatever you choose (shaman-elemental, druid healer etc.). In the end there soo many ways you can do this, I suggest just sit down and choose what you want and roll with it. You can always change them around. If your planning to play 5, start with 5, you can always try and sub the bettered geared two near 70. If then that fails , at least you have a team you know works from 70 lvls of experience. Either way good luck to you