Well, I just came to the thread to post a plan that was basically that.
The reasoning:
1) In the jungle, all our stuff fares decently; grubs and drillers are resistants, embers are immune or highly resistant, ember+ are hot enough to char wood so good luck with that, shrooms. This is a good place to send anything and probably shouldn't dictate our deployment, but can benefit from any leftover from the other 2 areas.
2)In the seabed, grubs are basically useless. Last time they achieved a whole lot of nothing and nothing has improved since then. Drillers may have some marginal usefulness, but short lived as they are and without being able to make stable tunnels, their usefulness here is diminished. Still fares better than the grub. Ember however shines. This seems more a very hot 24/7 desert, with temperatures one could reasonably expect to see in the hot regions of an habitable planet. The internal temperature of the ember should be high enough to make the seabed feel like a warm comfortable spring day. Ember+ is likely overkill. Its temperature is 200+ °C, so assuming the seabed is 60-80, it would feel rather cold. In essence: no grubs, few drillers, most of our embers. Have an higher proportion of base embers and send elites where they can have an added value, since on seabed they likely have little benefit over the base version.
3) In the Howling crevasses, grubs and drillers fared particularly well. More of the same is encouraged. As for embers, the wind surely won't help with thermal regulation. Plus the risk of shards flying around and splattering their hot innards on the rest of our forces exist.And they don't have the adhesive slime of the grub. Finally, I can't see any use for them there beyond as a mobile campfire, so they should only be here for research purposes.
(1) Something Like Specialism: MoP
(1) Even more specialism: Andrea