set Windows authentication for postgres
Yes

Service_account_name = DomaninServiceAccount = Domain user

A service account is actually a domain user, just with some extra settings like "no interactive login" and "password does not expire".
Dunno why they would use "DomaninServiceAccount" too. It's just Service_account_name 

Is it certain? Just have to test, but it looks usual for non-Windows applications (Atlassian does the same, and I have other Java apps that have AD authentication too)