Case in point - I referenced this to members of the NYMS and one of them looked up the species in an obscure book on North american slime molds which confirmed that the spores of this species have been seen to be Subglobose. This clarifies my final big hesitation about the species and confirms my ID. So i'm going to reedit this whole post to make it into a species post and add the new information source.

Similarly the white stuff is likely to be a form of resupinate fungi - which came after the slime mold sporulated. Also a tidbit from a NYMS member that bears out as a good hypothesis.