Multistore licensing

We have tested the plugin and it appears to be working fine for our needs.
So we would like to purchase.

I am however not yet sure about the license.

Our client is running multiple shops under the same brand.

i.e.

mydomain.nl
mydomain.be
mydomain.fr

And new shops will be added in the future. Currently all shops are running in a single nopcommerce multistore instance.
However it is possible that some shops will be installed on a separate instance later on. (i.e. mydomain.co.uk)

What type of license(s) do we need to purchase for this scenario?

Sorry for delay with answer.
If you use one database you should by single domain license.
You can use mydomain2.com, superdomain.it, likedomain.es.