Green isn't coolant, the coolant in the 12 is orange, so it's probably A/C, or just deposits from water draining. If it still works, I wouldn't be too concerned.
My 12 has weeped from the oil pan gasket from the day I bought it. It doesn't drip on my driveway at all, so I haven't done a thing about it. I am running Mobil 1 High Mileage in the hope that it might swell the gasket a little and get it to stop, but I probably won't do anything else unless it starts dripping. Replacing it isn't exactly easy, shop manual lists it as 2.7hrs, you gotta drop the front axle (on 4x4, anyway).
Running boards are separate motors (1 per side) and they are easy to change but
very expensive unless you buy some
Chinese knock-off motors, though those actually look pretty legit.
4x4 issue is probably the vacuum solenoid or check valve, I haven't heard many stories of failure on the IWEs in the newer Expys.