i'd recommend naval bombers, interceptors, cruisers and Battleships and submarines.
Put Nav bombes in The straits of the philippines and for standby to Defend battleships against submarines.
Place submarines further away from your territories to scout Surface fleets.
Battleships to dispatch enemy navy and cruiser plus interceptors for anti air capabilties you should sprinle a few DDs as well. But most anti sub damage will be dealt by the nav bombers.
Rail road guns as coastal artillery.
If you are much more defensive you can cut costs by downsizing cruiser and Destroyer fleets as your airforce should be able to commit against defensive Anti sub and air operations against the navy. Dont forget the RRGs here as well.
One unit that should help against enemy Nav bombers (pan asian real dangerous) are Stratbombers, upgrade them and they shall serve you well.
Island airbases connecting your territorial holding is very good and upgrading airstrips + creating parallel ones exponentially ridicules any enemy Operation to disable your Airforce
