I'm too sleepy to get a hang of who is who but still it's Yu Nagori, it has to be good
Its not just sleep lol.. I dont know what the mangaka was thinking but its NOT a good idea to try to introduce lots of characters at once - its not very clear at all who is who especially if one was changing size.
When you start a new manga or anime series you really need to take a minute to clearly establish who is who.
It was 2AM when I wrote this comment, so yes, I was sleepy as h*ck.