I'd just go HotW/NS spec on all 5 and swap gear whenever necessary. Heal on one until it's low mana then equip its feral set and switch to another slot to heal.
In theory, the 4 others should have time to regen back to full mana by the time the 5th is OOM and you have innervate for emergencies.
I agree to go HotW/NS on at least 4 of the druids. Since you plan to have 4 melee'ing it may make sense for one to go deep enough to pick up the 3% crit from Leader of the Pack for the group.
Th combo point os the cats may be a pain. You could use isboxers advanced system to make it manageable. I found with my druid team, that emergency moments were a pain as shifting out made you a fine paste.