Again, if it was simply a bomber then why three engines for >1 TWR and TVC?
Well, playing Devil's Advocate here:
-Three engines provide more electrical generation capacity for advanced sensors. That could apply to both fighter and bomber roles.
-Three engines for >1 TWR? Easy, supercruise and/or sustained supersonic flight. Why do you want to do that? Apart from efficiently crossing large distances quickly, it has an arguably much more significant tactical advantage: you impart greater kE to a missile at launch, giving it better range, or giving it more energy with which to maneuver in the terminal phase. Particularly if you launch it at higher altitudes. Again, a benefit that would apply to both fighter and bomber roles, as a bomber could fire something like a small ALBM or an anti-ship missile and give it a boost in range. Lockheed studied equipping the Blackbird with the AGM-69 at one point and the increase in range it got from being fired at Mach 3 and 80,000 feet was hilarious.
-TVC? Assuming TVC on the second prototype without a very clear shot of the engines like we have of the SAC airframe (I say that only because it is vaguely possible that the nozzles are designed for rear-quarter LO rather than TVC), the answer could be as simple as TVC was necessary to make the tailless configuration work as desired. Also, very small control inputs could be handled by TVC in certain combat scenarios, rather than using conventional control surfaces whose deflection could cause a more noticeable RF signature spike. So again, TVC could apply to either a fighter or a bomber role.
Basically, if I wanted a stealthy tactical bomber to hit out at naval formations or other regional targets, I might come up with an airframe like this. And if I wanted a stealthy interceptor, something along the lines of a MiG-31 type, I might come up with an airframe like this.
I'd say that side-by-side seating only proves this thing probably isn't intended to get into a close-in knife fight. In a turning fight you want unobstructed views in all directions as you have to make very quick reactions and decisions. But otherwise, all of those other features could easily be explained for either mission.
Or, holy crap, it could be a multi-role fighter intended to be something like a J-16 replacement. Then you'd all have to admit everyone was both right and wrong regarding the mission the jet flies
