This interview doesn't mean anything towards validating or invalidating any campaign out there.
I'll say this, "Volition credibility" might not have been the words I would have used, since it does seem to imply some sort of

stamp of approval for certain campaigns. But when it comes down to it, not even Jason Scott knew what Volition wanted to do with Freespace 3. In a lot of ways, we're as much in the dark as they are when it comes to the origin of the Shivans, Bosch's intentions, or the return to Sol. What the team had was nothing but conjecture, the result of some brainstorming that the writers and design team did shortly after FS2 was released and at a time when there was still some hope that FS3 would have been made.
What we got from Jason was a vague recollection of what V wanted to do with the franchise if they had gotten the ability to make the sequel. I'm sure if we picked the brains of everyone on the development team (at least the writers) there would have been people there who would have proposed theories to the Shivans similar to the cornucopia of theories we've proposed over the years. This is one man's recollection of what the team thought of several years ago, and I doubt it was the only theory on the table during the discussion for FS3.
Everyone in this community is doing what the Freespace team at V would kill to do; develop the story, improve on the hard work they did, and see their baby become the best it could be. V obviously has great faith in us to do them proud, otherwise they never would have released the source code or given us FRED. Just the fact that we have so many theories and so many ideas for the game is a validation of V's work to make a game that stood the test of time. The community wouldn't be what it is today if we didn't allow for dozens of sometimes conflicting ideas about the story.
No one should be turned off by this interview, and no one should be discouraged from promoting their own ideas. Enough people working over a number of years on a similar platform are bound to come up with similar ideas; from what Jason remembers of the FS3 brainstorming, one of those ideas just happened to have some of its elements developed in Blue Planet and other mods by happenchance.
tl;dr: There's still nothing official from V about Freespace 3's story. All we have is a recollection of some brainstorming and conjecture. The only thing V has given its stamp of approval to is the community at large for being so fanatically loyal to a video game that, in terms of franchise life, should have died out years ago. Our conjectures and our theories have kept Freespace alive for much longer than it should have lived, and that's all that matters.