^^ Agree with you 100% that it can be hard to type tv characters and writers may create a mishmash of traits. However, I DO think all of the characters in Felicity are pretty realistic and *could* exist - so in that sense they should be typeable. In other words, I don't think there were so many creative liberties taken that the characters became contradictory. (The ONE exception I think is Felicitiy's letters/recordings - I think that's quite a stretch and many F's wouldn't do anything like that)
I could definitely see Noel as ENFJ, but not as ENFP. However I think Noel would be more eNFJ, as I don't think he's a strong extrovert. I could also see Ben as ExTP, but I don't see any strong evidence for 'N' or for 'I'. If we're talking stereotypes, Ben was the popular, good-looking high school jock who was also a relatively decent guy.