Well... I'm not looking to undermine the Word of God. But as I remember it:

After 2197 (Pure) the FX300 racing league on Makana got so popular that they had to build more tracks elsewhere in the world to stop overcrowding. As they expanded, it was effectively rebranded as the FX350 league to accommodate for the change in location, and by 2206 (HD/Fury) it was announced to be the final transition into a new racing series the following year (which would turn out to be Pulse's FX400).

So, since HD Fury is between Pure and Pulse, the added teams in Omega would presumably be a retcon that doesn't have to effect Pulse.

We know that Tigron was involved as a sort of training team for Qirex in FX300 for pilots to learn how to fly heavier ships, and that the team and its remnants were dismantled when it fulfilled that purpose. But with the new content, it's revealed that an unknown entity brought Tigron back for FX350.

We also know that Van-Über made an appearance in FX300 but, for one reason or another, didn't transition into FX400. So, with the new content placing them in the FX350, what if Van-Über had always planned to stay, but something happens at the start of FX400 that prevents them from competing? The question being... what made them retire?