I'm way behind in reading the Nabokov listings, so I just got to the Edsel Ford question (three questions on Pale Fire).  The original query and all the replies assume that Edsel Ford is the auto company man, for unaccountable reasons given an assignment as a poet in Pale Fire.  The fact is that Nabokov was talking about a different Edsel Ford, a real one, who was publishing poetry at the time Pale Fire was written.  I remember seeing a book of his; he wasn't bad.
 
As to recurring characters, one I can think of is the old poet from Mary who is mentioned again in The Gift.  If I remember correctly (an I probably don't, being an old poet myself), his name was Podtyagin.   
 
Charles Nicol