Not sure that a few of your points are relevant for a large part of the intended operation but I do like the idea of using old Android hardware though! The ide

Not sure that a few of your points are relevant for a large part of the intended operation but I do like the idea of using old Android hardware though! The idea is to have a low power server for anyone to interact with over the wifi. If you could grab an old android phone, install IIAB app, configure as desired then put where you want - this would allow so many more non-technically savvy people to be able to build/deploy it. Depending on the phone it also could be easy to ruggedise with a case or maybe the phone itself might have waterproof ratings too.