Sir
That's not necessary. What's in the short pipeline are articulating strakes.
Your suggestion that the forebody, in gaining stability at high Mach introduces instability aft is a good point. At high speed the A/C can swap ends unless the Tail continues to anchor the aft and the front. The new strakes will be retractable above Mach 1. The A/C test bed for this feature, along with flex-foil is the F-18, none other. Why are the tails canted on the F-18? Mainly for two reasons. One, the "interference" you identify. The directional surfaces are in each others "ground effect" unitl a certain speed, and the effect leaves the foil from top down, relieving the thinner portion at the tip of very high load due to flutter. Second, each surface provides angular lift due to its departure from the vertical, similar to a winglet in that regard. Also, the Rudders can both be turned in (pigeon-toed), providing down force aft to increase rotational authority off the CAT. The F-18 is a treasure of aerodynamic demonstration, and will continue to be for a good long while.
Airfoil