If dreams misses E3, it's in development heck. Beta was planned for last year.Well I could see Dreams, GT Sport and Knack 2 getting trailers/gameplay videos the week before E3, The Lost Legacy potentially as well, if TLOU 2 is going to show up at E3, maybe Detroit too. Sony has done similar things the last couple years.
I think God of War, Days Gone and Spider-Man are almost guaranteed to show up in the E3 conference. All the other games could show up or not, I think either is possible.
But yes, if Dreams doesn't show up again before or in June then I think we can genuinely start worrying.