Connecting to a Remote MS SQL Server Database on non default port

What are the minimum permissions that the Suitecrm MS SQL account needs?

Also is it possible to connect to a named instance which is set to a non default SQL port?

As long as you specify the correct username/password details and your web service is pointing to the correct database port, SuiteCRM should install.

SuiteCRM will need read/write/execute writes on the database.