These photos are mirrored from the Boss Fight Studio Facebook page:
It appears that wave 3 will include:
-King Leonidas
-Youngest Gorgon Sister: Eurayle
-Myrmidon Warrior
-Gorgon Army: Ringneck
Possibly more. I have reached out to BFS for more info.
You can catch up on Wave 1 Here
You can catch up on wave 2 Here
You can discuss everything about Joe Con 2014 Here
Make sure you visit the Boss Fight Studio facebook page to view even more photos Here