Using Azure AD to push Group Policy settings
Azure active directory cannot be used like this. It is not a replacement for Active Directory (well, at least it isn't at the time of writing).
What you want to do is use the intune service in combination with AAD to achieve what you want. I do not believe you will be able to do full GPO, but there are a ton of settings you can configure.
Azure AD Directory Services is a new preview feature that functions more as a Domain Controller as a Service offering and does allow you push GPO's. The GPO and OU structure is more limited to classic AD, but it can be done. It is in preview so bear in mind the SLA consequences for that.