Um… I think that every type has different things they consider “not for public consumption.”  Usually it’s got to do with your dominant introverted function.

In the case of ENFJs, I would say that their secrets are less about keeping things secret and more having a very firm sense of boundaries and of who needs to know what.  People who you work with don’t need to know about your nerd life.  I think that if you are a person who is constantly synthesizing potentially invasive information about other people (NFJs in particular), you learn to keep your mouth shut to avoid causing upset and you might also learn not to put a lot of yourself into the open so that you are not stepping on anyone else’s boundaries either.

I don’t know about the ESFJs, but I’ve seen a couple of ISFJ boys who were slightly embarrassed to admit to collecting baseball cards which seems maybe a little old-fashioned, but… not that weird?  I think ISFJs, in general, like collecting information, and greatly dislike that you have theirs unless they specifically share it under the understanding that you will not share it with anyone else.

Very sure!

For the record, Jared Kushner was always typed as an INFJ, and Freddie slipped past me because the accent always trips me up.  Kind of a once seen, can’t be unseen situation, though.