Not possible. The SQL browser discovers the port number for you when it is a named instance or non-default port. It can't discover that when you don't tell it which...
On a GMSA, make sure you assign the account permissions in Windows. Depending on the application I have found that logon as service, logon as a batch and log on...
Personally I would strongly recommend against transactional replication. It works 95% of the time, but the 5% of the time that it is broken, it is just an unbelievable hassle...