If the RN wanted a higher performance monoplane torpedo bomber instead of the Albacore, is it possible to also have the DB capability of the Swordfish? I'm thinking not, as no one until the Barracuda of 1942 fielded a monoplane, single-engine aircraft design that started off as a torpedo bomber that could also DB. It had been tried the other way round with torpedo trials on the Stuka. Did the Devastator or Kate try DB?
So, it seems if the FAA wants their own B5N Kate they'd better also field a separate DB aircraft. This won't be be possible on the AFD carriers with their small CAG, unless your fighter is also a DB.... and we saw how the Skua turned out.
As above and before - design the darned TB/DB around the Hercules.