I did all mine before the mana totem fix/nerf, so I wonder how it would
be now? Probably still doable just either need to drink a little (cause
I never had to before) and still have time left over. BTW I did it with
DK, 3 Elemental and 1 Resto Shammy.
Yeah, I had to stop about 3 or 4 times to eat/drink (Thanks to my Mage wife for the pre-instance Table!!!!), for about 5-10 seconds each time. Not terrible, but does take some time, especially since you have to be out of combat to eat.

why do those guys in your screenie look like humans?
When you do Culling of Strat, it puts everyone into a Human illusion. I guess so you dont stand out during the time travel. They'd probably think it was pretty weird seeing 5 Draenei running around helping out.