Best to do a complete evaluation of transom and stringers before spending any beer tokens.-----Looks like a complete overhaul in your future.------I think you will be disappointed with the materials used by some boat builders,
I think 96 was the first year without the red plug.---------Near impossible to give advice on 12 volts / wiring from 1000 miles away.-----You need a factory manual with wiring diagram.
I am rebuilding a 1963 model this fall.-----I have many 10 HP models.----I recommend that you fit the 61 / 62 / 63 model rods and pistons.----End of the story.
I would install the rods and pistons from a 61 / 62 / 63 model 10 HP.----Much better with a hefty bearing on the wrist pin.----Same bearing as used on a 125 HP V-4 model.
Counting all the needle bearings and not losing them is the only challenge.------Pretty simple motor.---Trick might be to take rings off the piston and taking assembly out through the crankcase.------I have manuals but not needed for these wee ones.