You're right. Larry David is not an INFJ at all. He's an ENFP. His dom function is Ne because he improvises through curb your enthusiasm, rarely plans comedy, says he gets ideas which he writes notes of. Fi aux because he started off with comedy about his failed dates, was jealous of people who dates, does comedy for personal happinesd and uses nihilistic humor as a tool to show the negativities of peoples emotions that is covered up.
George reflects him making him at least close to ENFP. George is considered nuts, in that he gets crazy ideas to change with. He ends up in the strangest situations because of his bizzarre ideas. These ideas reflect his failures in relationships and general unluck.
Kramer too gets ideas and attempts to consider it in an intelligent way. Hes the most stereotypical ENTP. I think there was an episode where he tested some giant ball by throwing it out the window. Pretty sensible... huh?
Newman is the one who people go to for advice. He is the one who knows strategies and different ways to execute plans. Hes a bit showy with this and is friends with Kramer for a reason... ENTJ. The Se side makes him show off a bit more and has a bit of sly approach. Lots of ENTJs can be like this. Also have you heard some of his speeches? I will rule, defeat Jerry, poetic text etc. shouts ENTJ.
Jerry is the observant one who notices the inconsistencies and illogical patterns. This is why he does stand up. He is also very practical. If it won't work today tommorrow. ISTP. He'll always reject Kramer's whac ky Ne ideas and do stuff in the moment. And hes not the ISTJ you think he is. He doesnt go crazy when plans fall apart. Also in one episode it reflected how he was passive, didn't get angry and lacked concern with emotions.
Ellaine is a bit harder for me to type. Shes usually honest and smart but has a different approach at different times. Shes quite relaxed too. Rarely plans so Se seems definite for her. She also usually has some opinion that is also honest. I'd say shes ESTP, which is why her and Jerry get along so well and have similar attitudes.