NO water in the oil,,,,,if the oil level is not OVRT full,,,,,,, pull the spark plugs and turn it over a couple times,,,, put the plugs back in and see if it fires up on the hose,,,,, check for milkshake one more time,

I would probably be proactive and send the starter out for a rebuild to save headache in the spring.

Backwards will not hydraulic the motor and break stuff if you leave the plugs in. Forwards will. Done it more times than I can remember with motors that were hydro locked

but we are talking plugs out and cranking by hand won't break anything. remove exhaust manifolds. they could be full and filling pistons. you will probably lose starter. maybe alternator and anything else that failed float test...trim pump solenoids, bilge blower, etc. a lot can be disassembled and cleaned.

Minus well pull the motor replace everything electrical all wiring everything. While your at it may have been water intrusion in the transom, stringers coaring in hull sides/ top deck. Start cutting her up!

It's fresh water. Get it in a warm dry place with fans. Everything should be fine.