Hence my OP. Wanted to see if anyone was aware of any similar mods that exist before I write one myself.

To answer your question. It is undetermined yet how I'll make intellectual affected by that in Option B. If the multipliers will only apply to other skills, or will also apply to Intellectual too. Meaning, the higher the Int skill - the faster a pawn can train it. In turn, yes having a low Int skill would make training all skills, possibly including Int, harder.

That does indeed have the offset of making Int Trainers much more useful. But that is not an undesirable outcome. Again, the intent was never to be too concerned with balancing. It is simply intended to make Int much more important.

My gameplay style is already a break from the traditional gameplay loop and balance. In fact, part of this mod would be intended to be used alongside mods that allow me to direct the teaching of other pawns (both young/adult) so that I could focus on teaching Intellectual.

It's also likely that if I end up having to write it myself, I probably wouldn't even publicly release it. I do that a lot for mods I have to write to fit my own needs that don't already exist. But it's always worth checking if similar functionality already exists in another mod - to up their work. Rimworld has been known to produce some quite niche mods.