About the other dreams. The structure of dreams were never hinted to be different, and if they overlap perfectly as they do in Max's Dream, they should have comparable structures, unless specifically noted. If they "overlap" all of their dreams inside of Max's dream, and Minus was confident he could end all of it with Max's Notebook, this heavily implies he has control over every Dream connected to his own. The girl's dream , the one who can control time, that was her dream connected to Max's dream. It was said to be able to stop the entire timeline from moving with the Crystal Heart. This is pretty good proof IMO.
We have no real evidence as to how this overlapping of their Dreams even began. It clearly was going on for quite some time, evidenced by the movie, but it is unknown for how long.
Minus' showing of being able to destroy Max's Dream World ( which would include the other Dreamers' Dreams as they are overlapped inside of it. Evidenced by the children being ij sepcifically Max's Dream, the girl having the time power inside of Max's Dream in her own dream , and maybe a few more examples. Plus the fact Max materialized this Crystal Heart, which is an essential part of the snow girl's dream, from her own dream supports Max's superiority. ) with Max's Notebook, which he used to to attempt to destroy Dream World. Also the fact that despite having all of these dreamer's there sedated, he still viewed Max as more of a threat than any of the other Dreamers ( Get him before he realizes his true powers, and tears my new kingdom apart. This is Minus when amped by Max's Notebook ] , which included the girl . She was onky considered an annoyance. Sorry, I don't believe she was named. Will have to go back.