Custom privileges for Custom roles for users in the Integration SaaS

Integration platform has only two default roles: "Admin" and "Developer" (notice that there is no "Oper" role).

We are sharing the platform with other teams and we provide them access. But they SHOULD NOT BE ABLE TO SEE, EDIT, DELETE or PUBLISH projects that don't belong to them. Therefore we create "custom roles" and limit their visibility only to a few projects that they own. We assign this role to new users (depending on the team they are coming from) and we remove the "Developer" role, so they cannot alter/interfere with other business units.

The problem: a user with a custom role CANNOT PUBLISH THE PROJECTS with WRITE (or total) access in his custom role.  We need them to be able to publish.

So either we (the admins of the platform) publish somebody else's work (without having complete knowledge of what it does, be available at off hours, etc) or we give them access to projects that they should not see (because they have higher level of confidentiality, security, availability, criticality, etc.)

Is there any way you can allow admins to grant "Publish" or other type of privileges to users that have custom roles and not "Developer" nor "Admin"?
Meanwhile, you are doing that, would you be able to allow "Admins" to remove privileges from default "Developer" role to make it more restricitve? Or could we create a new one with more restrictions and set it  as default? The more complex solution would be to create "Provider Organizations" and projects should be inside them, just like Catalogs exist in API Connect Provider Orgs. Take some inspiration from APIC. 

Thank you, 
Best regards.