Hello,
I have many years of experience with Python coding and using Linux.
Regarding RPi, I have used it for many projects including home automation, video surveillance, media center, small website hosting; I have also used peripherals such as IO Pi Plus, GrovePI, SenseHAT, UnicornHAT. Some of my Pi projects can be found here on my Freelancer.com profile.
For the administration part I would create a Django web application; we would have to discuss how the central website would work - for example would all devices have access to it and poll for changes?
Best wishes,
iticus