You're correct and completely agree about the non-request for reanimating the entire game.
So, I started on something like this a little while ago between work and reached out to @LarannKiar to pick his brain about some things related to reversing SF and the components needed from SFSE to get this off the ground; basically after some investigation it appears we just need to figure out a clean way to disable first person mode when translating the third person camera into the third person body, because having a body to begin with is really the primary here. We were able to identify the Get3D method in order to get the body node here
virtual uintptr_t* Get3D(uintptr_t* object3DOut, bool bFirstPerson); // basically both object3DOut and the return value are RE::BSFadeNode*
And the overall approach I had planned for was this:
Force the third person camera enabled
Scale up the third person body to account for clipping
Translate the third person camera position into the player head/eyes node position
Handle each camera state to either block first person cameras or restore the forced third person camera
Handle player translation and rotation events to sync camera position to the player head node position
Optionally hide third person arms and/or third person head and optionally show first person arms
I'm guessing the hidden first-person states that Larann encountered is what needs to be dealt with first, and then some progress can be made. Essentially those states need to be completely suppressed/disabled, when attempting this approach, otherwise the view is broken.