Could This Gamera Villain Appear In Gamera: Rebirth?

"Gamera vs 5 Kaiju." Two out of five of Gamera's opponents have been over the course of two months (Gyaos and Jiger) with three open slots remaining. Some fans speculate the whole roster will be filled with his opponents from the Showa and/or Heisei eras. Others say we may see a new villain emerge in the upcoming anime Gamera: Rebirth. One villain, in particular, has been gaining some notoriety due to how similar Gamera's and Gyaos's designs in the anime look when compared to the designs in a proof of concept trailer that was shown at New York Comic Con in 2016.

This villain that was shown in the proof of concept trailer has no name, but it is described to be sort of a Lovecraftian monster. A creature resembling an octopus or fish with other features that do not look normal and usually horrifying just by looking at it. This monster even has an ability to fire blasts of energy.
Whether or not this monster is a new monster or an older monster that is redesigned is also unknown. However, considering that Gamera: Rebirth is drastically redesigning the classic monsters I could see Kadokawa using the monster from the concept trailer to be repurposed for a classic Gamera villain called Viras.

First appeared in Gamera vs Viras, Viras was part of an alien race that came to Earth to conquer the planet. However, their efforts were thwarted by meddling kids that they held hostage against Gamera. The kids in the movie were able to escape and prompting Gamera to destroy the alien spacecraft. In their last ditch effort, however, the aliens combined into one giant monster to fight Gamera.
Viras lacks the energy attack that the monster in the concept trailer has, otherwise the two monsters are very similar in design. Both have a squid-like cone that opens and closes, have tentacles or appendages that look like tentacles that can be used to move around, and they have a similar chirping sound that they make.
On top of that, using the concept design as Viras's new design would fit in with the consistent designs of the other enemy monsters in the show. Take a look at Jiger. It looks more intimidating, scarier, leaner, and moves faster as compared to the original Jiger. Same idea with Gyaos. It's much more scarier, bony, and faster. A new Viras design would go in this similar route if introduced in Gamera: Rebirth and the concept design of the monster would actually fit as Viras's new design.
If we do see this concept design of the monster again we should expect this design to have some changes. The concept design is exactly what it is. It's a concept designed for a monster as an idea of how this monster could look. It was never established as the final design. If Gamera and Gyaos in the anime are using the same assets from the concept trailer then some changes we