I think all or most of the little asides are a reference
to something; the airplane is a clue which I can't decipher,
but if there isn't a (reasonably) famous Robert and Marie
in a jungle in the 1920s-1970s time frame, I'll be surprised.
The naked "native" is a clue; and the dialog might well be
lifted/approximated.
Along those lines, there are three paintings we see described in Severian's visit to the Library: one is explained (the astronaut on the Moon), but the other two are a mystery to me. Has some other person figured them out?
I did catch that when Valeria translates the "Latin" (which
Wolfe tells us is used to stand in for another langauge),
she gets it wrong. I think this is meant to be humorous,
and a hint that she's trying to impress Severian; it may be
also a hint to us that some things aren't what they seem.
-John