Was trying to understand it too. Little green numbers on bars are time left on renew (I think?). Output area and CD monitors gave a suggestion of what else was being cast.
Except for a small section in dps chakra, I think the whole thing was done in serenity (would need to watch again to be sure: the HW: serenity icon disappears when out of serenity chakra), with very heavy renew use. Frequent use of binding heals, flash heals, cascade and HW:serenity. Noticed PoM, PoH and greater heal being used, but less frequently.
If the void lords are always in a state where they're being hit, their shields dps means they're the strongest pet. It's not by much, and requires the constant damage, but a 3~5% dps increase (On the pet) is always useful.
Also probably used for handling adds during the temple/terrace sections?
Void lords shield does insane damage if they stand in breath for example on thok or annihilate where you take dmg no matter what.