Do I need to read all of these to make sense of the story? It looks like 1,2,5 and 6 are paranormal romance and 3 and 4 are tagged as teen. I have the 4 paranormal romance, but didn't even realize the other two existed until I notice the numbers jumped. The cover look like a completely different series, I think that's why I missed them. Should I get them before I read 5 and 6, or are they enough of a side story that the next 2 would make sense without them?

the teen ones aren't needed for the rest of the series to make sense

I only read the teen ones and wasn't lost without the others.

Yeah, what is up with that?  I've never seen a series jump back and forth like that.  I loved the series but didn't read the YA books and I really don't think I missed a thing.  I don't even recall any teens/young adults showing up in the adult books.