When replacing the raw water pump with the air bleed system, can it be replaced with a raw water without the air bleed, by just closing the air lines?

The air lines are only active with pressure applied. Removing them should cause no problems.

The 'air actuator drain system' does not intersect with the Sea Water Pump at all.

Remember, the "air drain system" does not DISPLACE the water in the sea water side of the system. It merely opens two drains when pressurized/opened, allowing water to drain out efficiently, but NOT COMPLETELY. (This is why it's mandatory to still do a complete winterization in cold climates.)

You can disconnect any part of the "air drain system" at any time without affecting how the engine operates.

On a second note the drains for air system are prone to leak over time especially from lack of proper winterizations and or corrosion issues.

Also some of the recaled hopped up 496 with higher water pressure and higher rpms those drains will leak at WOT. We used go pro cameras in the engine compartments and a bright lite source to find water leak sources while running the boat thru out all rpms on the water, bare min 50 % of the time it was those air water drains. The older the engine gets - they will start to leak. Just saying

One of my air actuated drains always leaks a little the first or second time out after being winterized but eventually stops. Never enough to make the bilge pumps cut on though.

Never trusted them air drains , I have removed all the air bleed fittings on a twin motor boat lost about 15 lbs in weight and made it easy to get to other parts on the motors plus it looks tidy .
Just use the blue drain bungs. .