Unemployed after 1st postdoc, what should my affiliation be when introduced during campus visit & job talk?
How about "I've done my PhD at [PhD university] with [PhD supervisor], working on [PhD subject]. For my postdoc, I went to [postdoc university] to work with [postdoc supervisor] on [postdoc subject]." If you want, you could also say "I did my postdoc at ...," from which a good reader can infer that your postdoc has ended. 

I don't think you need to stress your temporary freelance status any more than that. It's clear enough in your CV and you got an invitation for a campus visit + job talk, so apparently the interviewers do not think it's a big deal. Of course, you should have a good explanation for that gap during on-site interviews.

Finally, try not to worry too much whether you're being invited for fake interviews/to be ridiculed/as a filler candidate. I think mostly you are a bit uncomfortable about your current situation and that's putting some doubt in your mind that (I'm guessing) does not have a basis in reality. Simply concentrate on giving a good talk and having fun chats about the research you'd love to do.