That’s an interesting scenario. Yeah I think emphasising torpedoes and destroyers/light cruisers makes some sense since the existing heavy ships are terrible if they get hit. I think early battleships are pretty vulnerable to burning down, so maybe go heavy on HE ammo and rate of fire, you can probably sink them with new ships. Early battleships have a hard time penetrating each other anyway. So perhaps some kind of heavy cruiser makes sense.
The rush to build real capital ships once the treaty expires should be interesting. Don’t forget (like I did) that the treaty goes out the window once you go to war.