From Gravity, we should salvage one BW, so we have four, and then the Mummies, so we have a full Death duo if we want it. Maybe a Gravity Pull for a grabbow. Everything else should be transmuted or converted, provided we don't get Discords from Entropy to make a Nymphcord.
From Air, we should salvage the Nightmare, maybe the Fog, and some Grabbies and Novas to make up for the loss to Darkness. We can also Salvage some Air Pillars and Pends, to make a UG trio, like a couple of you have suggested.
From Light, we should salvage the EEs, another Wings or two, the Miracle, and maybe a Blessing for our Grabbow. We can convert or transmute everything else.
For our loss to Darkness, we can get some Grabbies, Novas, and the Nightmare back from Air, so we can discard some of those. We might be best off discarding Pillars and converting them back from converthing some of the salvage from Gravity and Light we don't need.
