Multi-Geo, Satellite Location, Namespace

Can I check.
When adding a Geo Location in SPO Admin.
(I don't have access in my test environment to MultiGeo _ so going off a youtube video on this).
Under the "Enter a domain for <location>"
1. Can the value in domain be anything? The field appears to be a free text field.

If the primary SPO URL is Contoso.Sharepoint.com.
2. Does the domain have to be contoso+ <suffix> 
2a. I assume "ContosoEUR" _ is valid
2b. I would assume "ContosoEU" _ is also valid.

3. Can the name be <Prefix> + Contoso? eg "EUContoso"

4. Can the name be something completely different eg "Wingtips"

Thanks