The body enhancements that J6 puts their assassins through affects their skin and hair color to different degrees.Goh has blue hair, pale almost bluish skin, and even his eyes look jaundiced. It can probably be assumed Goh has been with J6 the longest and may have been through the process multiple times. Jean has light gray hair and pale skin. Vanessa has white hair, and while her skin is still dark in 4, it's actually lighter in 5 after she was captured by J6 again, which could overlap with Fridge Brilliance. Sarah was never put through the same body enhancements, at least not yet.
Jacky Bryant is an alternate universe human version of Sonic the Hedgehog.Jacky loves going fast, has spikey Anime Hair, is nicknamed the Blue Flash, is very enthusiastic, and both the Sonic and Virtua Fighter series are made by Sega. I don't think it's hard to see the connection.
Shun Di will die and be replaced by his student who was captured by J6, who also happens to be the double agent within J6 who rescued Vanessa between 4 and 5.Shun Di vs. Brad Wong or Kage vs. Ryu. The core gameplay will be done by AM 2 while Team Ninja will do the character models, story, and overall presentation. The story will involve DOATEC and J6 being competitors in a sort of arms race to see who can create the perfect fighter. Both have their own tournaments to choose fighters to experiment on and gather data, and each one accuses the other of ripping off the idea. DOATEC went for cloning and genetic research while J6 opted more towards robotics and cyborgs with the occasional brainwashing and child soldier. Their covert war will turn overt, and fighters from both sides end up involved in the conflict.