Fascinating - it just so happens I was digging up old stuff about Virtua Fighter the other day - like Daytona USA, Sega showed off some spectacularly early versions during development. Siba was both one of the first characters shown and one of the last characters removed. The Hidden Palace Zone of fighting games.
Was it ever said why he was removed exactly? Guessing it wasn't space concerns if he's still there buried in the final game.
It's worth noting that Seiichi Ishii, the coordinator and main designer of Virtua Fighter, served as the director of the first two Tekken games before founding Dream Factory in 1995. The likelihood of any design similarities being coincidental is low.
I've spent years wondering about Siba. It's really cool to see him in action properly, and without the weird sword based style they gave him for Fighter's Megamix. Still, I wonder about those name plates; pretty boy Akira may well have been intended as a different character, and just has a placeholder name plate. And I don't even know what to make of Majido as a name. Reminds me of Ra~shi~do~ in Street Fighter 5. Majid? Mazid? Still, I've kind of always thought Siba may have been intended to be called Shiva anyway. Japanese phonetics and all.
The best part of this is the character is called "P.Jack" or "Prototype Jack". aka they totally knew what they were doing. Character names for the original Virtua Fighter feel like last minute additions - most of the cast were given at least two names during development (or in two cases, Sara -> Sarah and Jackie -> Jacky). I may go hunting for more clues.