The Caspian Sea was called a sea in ancient times, because it was salty and large. It is considered a lake nowadays, the majority of people and scientists do. It's only the name that hasn't been changed.
they would still be landlocked nations, because unless you want to eradicate the caucuses or dig a line through iran it provides no access to the open oceans.
To sum it up: The Caspian Sea is a lake.