In P&P, I assume that 'be' occupies the head of VP as P&P doesn't allow for empty heads. From that I assume that copulas head objects/complements in the same way that a lexical verb would?
In LFG, copulas pretty much disappear in f-structure but do they at least select complements in c-structure (while the head of VP is empty)?
Edit: I suppose VP being empty isn't really the issue. Lexical verbs without an aux can and do occupy IP/TP, leaving VP empty anyway. In f-structure, the predicative noun/adj. etc. is the predicator, while in c-structure I guess the order of things still shows objects as complements of what is ultimately the lexical or copula verb in IP/TP. Does this mean that LFG presents a conflicting analysis of copulas in f- and c- structure?