Varuna:
He is known as the god of oceans. He is seen riding on an ocean creature that has an head of an antelope, but a body of a fish or an alligator. His weapon is a noose. Varuna was a very important god in pre-Vedic Hindu mythology. Though only about a dozen hymns address him in the Rig Veda, he had a position of stature among the deities. In late Vedic times, the worship of Varuna fell off and Indra replaced him as king of the gods. Varuna became god of the oceans and rivers, which was still quite important. The souls of those who drowned went to him, and he was attended by the nagas. Eventually Varuna faded away with the ascendancy of Shiva and Vishnu. [compiled from webonotics.com and siamese-dream.com.]
With reference to dance the abhinayadarpanam says
patako dakshine vamay shikharo varunaha karaha
Varuna is represented by holding Pataka hasta in the right hand and Shikhara hasta in the left hand.
I cannot really remark on the mudras themselves, but I wonder if there was something like a mudra alphabeth from where to make them up?
It is easier to comment on the objects displayed, like the historicity of Varuna. According to late Dr. LA Waddell`s masterful translations, like pp 79 ff and others from
http://books.google.at/books?id=0Ss8Mbn0eLEC&pg=PR18&dq=Indo-sumerian+seals+deciphered&lr=&as_brr=3#PPP1,M1
it was likely a symbol of the resurrecting sun, carried by a fish or boat through the ocean during night. The day and night was thought of 3 parts of the sun: ascending, descending and night journey. These three steps were also considered the three steps of Vamana avatar of Vish-nu, just another word for Fish. Christians depict Christ the Redeemer as a Fish. Link below shows how in Kerala a saint is still carried on a ship. LA Waddell translated second Sumerian king Gan as Gan-esha. See how elephant is first to venerate at the festival in the film. The feast itself is like a theatrical performance centered around a sacred vessel or bowl. There are chapters in Bharata Natya Shastra were a sacred bowl is venerated before the performance. I am in need of some of these passages.
http://www.youtube.com/watch?v=V6tSrE89Pa4