With all islands and ice shelves Antarctica is 13,661,000 km squared. For comparison, Australia is 7,686,855 km 2, United States is 9,363,132 km 2. The land area of Vanuatu is 12190 km 2. The sea area of Vanuatu is 710,000 km squared. So Antarctica is about 19 times larger than the whole are of Vanuatu.
Chile is the closest country to Antarctica.
There are lots of ice caves. I do not know of any rock caves although it is likely that there would be some. Maybe deep under the ice. The sea water gets as cold as minus 1.8 degrees Celsius. The animals are very curious and don't scare easily.