Literally everything in the Honorverse happens beyond visual range; this is something you can't make work in FreeSpace (even taking into account HUD hacks and scaling tricks) and stay true to the source material. By the time you tweaked it enough to make it work and fun, you've changed so many things that you can't really call it a "Honorverse" mod anymore.
I obviously don't know the source material and from the dicussion here it seems like nothing I would enjoy (I am not a fan of realist fiction anyway, military tech porn esspecially)...
But in the fifteen minutes between reading this in the first time, I think I came up with enough viable concept to make it work. However only as pretenious AF commentary piece ... soo yeeeaaah...
Since external camera and "view from target" have been part of the engine since retail (not to mention SCP camera controls), it is not impossible to make beyond visual range combat a thing technically - at least on a capital ship scale. You would have to add some tweaks with the regards to aiming assistance (targeting lasers, scripted course projections, projectile tracking the HUD etc etc) and train players to aim from a non-POV persepecitve but technically it is all feasible.
The non-POV aiming is going to be the most difficult thing to get right, because through it you propably will create a sense of detachment between player action and effect (that's where the pretenious commentary comes in; the detachment of action and effect and withheld or impossible gratification *gesture to signify "etc etc"* in relation to the expected form of agency in video games etc etc and all that*).
* Dismissiveness for comic effect; It is an intruiging line of inquiry but I am not quite sure how to follow it without letting critique slip into self-engradising performance.