[jhanschoo]

It's a bit surprising for me to see you describe final -g as such, because a lot of English speakers while they have lost the final plosive, still frequently pronounce the final nasal at the back of the mouth, hence analyzing -ng as a digraph representing that sound. Writing it as -n explicitly signifies the other more innovative pronunciation that just uses the usual nasal at the front of the mouth instead, that some but not all speakers use. Few speakers pronounce the plosive. I also wonder if assimilation may occur, e.g. a speaker may simultaneously prefer nuthin', and also lugging.