Birmy
Hero
I can see them going for the mimic for sure, for the brand recognition reasons you suggest. Assuming the artist and the style is the same for the alt cover, I was thinking maybe a displacer beast, since that's a distinctly D&D monster and the pseudopods and displacement effect would make a consistent visual with the whirling gold dragon and webs/legs of Lolth.Mimic is the other monster they're pushing for brand awareness. A big slobbery one seems like a real contender for one of the Monster Manual covers.