Hello,
I am very interesting in you project, so I can quickly and easily implement all features that you want, because I have a big experience in working with maps and geolocation. You can check my portfolio, most of my projects are geolocation-based apps, so I'm familiar with this area.
As for editing the content via web, I can't create this feature for you, because I am native Android developer, but you can update the app's content just locally on your PC, I'll show you how to do that.
I hope we will be a good partners. Thank you!