When the Nova labs were destroyed they were done so by a mysterious fire, the cause of which wasn't explained. Perhaps an opposing group against WAR decided to destroy the place and took the Nova plans for themselves before destroying it, all while the 2097 tournament took place. The group of which who did and for what purpose they stole the plans, god only knows. Iron Fist? A WAR splinter group? Someone else?
Here are some roughs of different type of Mantas heads.
'C' looks more like the real life mantis. The eyes should be bulbous, and with compound lenses. And antennae, that shoot lasers!