I have a Resource Group (RG) in Azure. I am the subscription admin and in the RG my role is Owner. I also have two other users assigned to this RG, and their roles are also Owne
Yes. You can. In the Subscriptions Tab on the left of your portal screen, select your subscription and go to IAM (Identity and Access Management). Select the role that you wish to give to the users in this case "SQL Server Contributor" and add the users. Contributor role will give them the right to create/delete resources but not the right to give access to the same resource to other users. Check this link for more details.
You can register the required resources provides in the same Subscriptions Tab, in the Resource Providers section.