Note that these aren't immediately understandable by a native speaker either. Palahniuk seems to like using unusual words and grammar to make his writing seem strange. I believe this is supposed to show the mental instability of the main character, but someone better acquainted with the novel could tell you more.
"-ie" or "-y" is an affix which creates diminutives, i.e. shorter and informal nouns. Sometimes it can be used on a noun X to mean "a certain thing related to X", but not always.
food -> foodie (one who enjoys food greatly)
communist -> commie
self -> selfie (a photo taken of oneself)
So in this case, moosie is something like "informally mooselike person". Bob is obviously a big man, and probably a relatively docile one, as moose are herbivores.
Cheesebread is much harder; at first glance it calls to mind bread that has cheese in the middle. It is not easily apparent to a native speaker at all. This site says that it relates to Bob having a metaphorically soft interior (cheese and bread are both soft). From what I gather Bob is rather feminized and the narrator seems to disdain this, so this would make sense. However, again, a reader of the novel could provide better context.