Side effects when migrating a domain name to a new tenant?

Next month I will migrate my domain name to a new tenant. The old one is just for lab purposes (it's an E3 Developer tenant) but I made the mistake of starting to use the domain and email addresses publicly and now I am getting a real E3 tenant and I'm going to move the domain to it. 

I am comfortable with the actual migration and domain move, having done it before. What I don't know is what will happen to my guest accounts in other tenants. I have been invited into a lot of other tenants, and I have also used my account to sign in into Microsoft services. 

I suspect it is a little more complicated than just signing in with a new account (from a new tenant) having the same account name as the old account that I used to sign in with?