Congratulations on your well! Having had 4 major water outages myself in 2020 on our farm, and doing all the repairs myself, I am very in tune with water usage right now.
The idea of a cistern that overflows to a
pond is a great idea. A means of capturing all the water for various uses is something a surprising number of people don't think about.
I'm not sure how things are in your neck of the woods, but where I live there are regulations that say only a licensed potable well installer can work on your well. Incidentally our system does not fit in any of the states definitions so I do my own work. That might be worth looking into if you haven't already.
Pitless adapter. Worth it.
What I do recommend is thinking through the system you want to end up with, and build that into whatever you do now. If that's confusing, what I mean is think through the system and add stub outs and extra connection points to make integrating an extra cistern, or another pump, or whatever, so when you need to make a change down the road it's really easy to do. I did that when I rebuilt the farmhouse water several years ago and I was thanking myself for it several times this past year.
Also, I recommend getting the pump you will grow into now. It's going to be the hardest to replace down the road. Adding
solar panels, batteries or controllers at the top are world's easier than pulling 300' of pipe and and a pump.
Don't skimp on the pump. Looking forward to seeing what direction you go!