wow, I can't even believe that I've read all your explanation above XD
your speculation and all are very amazing! lol
I have same opinion as you about the larger group part,
I think Jinguji and Iwahashi debut is almost a sure thing
maybe Miyachika Kaito will also debut with them
or Fumito something will also debut as "fresh" junior category ><

however, Johnnys is very unpredictable
let's wait and see _(:3 」∠)_