In short, mostly true, if looked at with some flexibility.

Im thinking Neuschwabenland first and then historic mappings of Antarctica, it's actual shape and location as well.
The Atlantis - Antarctica theory from my knowledge does not make sense based on Solon's description.
The alien part, when everything is considered, can be said is true. The people from the Atlantis civilization were of the so called "serpent seed" and of a different bloodline, the now famous Rh - which actually can't be traced back to common origin with any other blood type.
The Nazi Antarctica connection, especially through Argentina which is still possibly connected by land to Antarctica, where they came in contact with what they understood as pure Aryan race, or possibly us from a different time if that's not going too crazy, in my eyes correlates to the alien story