Hello!...I actually stopped posting about this as it got zero interest and I was sorry I made the post.
However, now that you ask I was going to remove all the "green" parts until it was just the pump and water tank only, then I can go a couple routes, Mount a flywheel with eccentric where the gearbox output is and power the pump off the existing pump arm OR mount my flywheel and eccentric over the top of the pump like a Pericaud pump.
I have a couple Wilesco spoked flywheels in my parts bin but it occurred to me the flywheels value may exceed the entire project value.
I can also make a flywheel to save my nice spoked ones for more lofty projects.
The pump it self works very well....I just wish it was not plastic and a bit more old time style looking...thought of lightly sand blast to give a bit more tooth for paint to stick and try to rusticate that way but it will never be a collectors item...lol
Just had a second thought, I was originally trying to get rid of the blue man "turning" the crank...however...if the Blue man was not highly offensive to you or just wanted an easy conversion, It just occurred to me the crank the blue man turns is an eccentric to make his arms work, the round pulley the hand crank his arms attach to would easily except a o-ring belt or flat belt, so if I left all the kit parts shown and just removed the geared DC motor (2) screws then it is ready to steam power as is!
Might be a kid friendly super simple thing and the kids can put the motor back to play with the solar part later....just an option that would cost zero