Hello,
The ACL feature in HikaShop is meant to work with the Joomla user group.
As long as the Easy Social Users are also Joomla account, if they have user groups assigned, you can use them.
The system is not built to work with the Easy Social groups ; it would require some custom development to add the feature.
That's why I proposed you to use ACL just to fill the point 2
This means that I want the user to have to login before purchase.
And told you about the need of a custom plugin for the rest.
Regards,