Female connector: If you look at the end of the plug, you'll see a rectangular opening in the housing with the female connector inside. You'll also see a smaller opening, maybe .075" x 1/8" (??). The female connector has a piece of metal sticking up that locks in the smaller opening and this needs to be pushed down to slide the connector out of the housing...through the wire end. You can use a piece of the old metal type wire coat hanger, a nail, or a welding rod. Beat flat and grind to fit small opening... I used an old hacksaw blade. Slide metal into small opening, wiggle if needed, and apply LIGHT pressure to wire, and connector should come out of housing. It's kinda difficult to explain, but do one and you'll understand completely.
I've never had to remove a male, but I'd think it's the same...smaller opening with retaining pin needing to be compressed/pushed down.
I can't give a definite answer on replacement connectors, but JD used Packard 56 connectors on some models and I forget what they used on others! #16 wire should work in most instances. Not much help! Bob