Using a Miro board with Google Meet: some questions

I’m working on an interactive presentation (with Activities). I usually use Google Meet, so I want to share my Miro board in Meet using the add-on.

I made some tests. Main things I found:

1) it would be great to be able to create Google Meet breakout rooms when you’re using Meet into the same tab of Miro board. Moving Meet to a different tab would work if only the host were to do it. But it’s something all participants have to do — moving Meet into a different tab, I mean — otherwise they don’t receive the invitation to join the room you have assigned them. And this makes things a little bit trickier, especially if participants are not so tech-savvy.

2) when I end/stop the collaboration and I then end the Meet call, participants still stay on the board and can do things till they log out. Since I gave them edit rights because they had to do/change/edit things on the board, I supposed that when I ended the collaboration and the call they would have been automatically logged off. Or is it my fault and am I missing something? It could be :) 

3) I’ve invited some friends to make some tests with me. I’ve used, on purpose, email address that are outside my domain (I’m a freelancer) and no Gmail addresses. I would like to use this interactive presentation I’m working on with clients. So I don’t know what their email addresses will be. Some friends told me that when I started sharing my Miro board, they were asked if they wanted to join with their Gmail account. Since we needed to do some tests, they used their Gmail accounts. But my question is: do participants have to use a Gmail account if they want to collaborate on a Miro board I’m sharing during a Google Meet call?

Thanks!