Just a suggestion, you may want to include your group composition in the future when requesting strategy tips, since it makes a big difference. If you're also running 4 x Shaman, I would suggest 4 x Healing Totem for all three of these encounters then. One healing totem usually isn't enough to help my priest enough, but 4 of them ticking away can add up to a lot of healing pretty quick (roughly 1k+ hps to group every 5s at 80?). If I recall, they also factor in spellpower on the healing totem.

My tips assumed you had "at least one shaman" in the group, since it was just a totem question.