Comment Get your neighbours to change. (Score 1) 451
I can't answer all your questions, and it seems no one else has either.
However you already know that APs cooperate when on the same channel, so the best thing you can do is get your neighbours to change to non-overlapping channels. I have done this by visiting my neighbours, explaining the problem and helping them to change channel. Result: reliable connection. You might prefer to get the concierge to advertise good wifi practice.
If you end up configuring all your neighbours then you get a chance to distribute signals intelligently: ie, reserve two channels for big downloaders, and the other reserved to ordinary users (even a single channel is more than enough for 20 people browsing the web).
Non-standard wifi and N: generally speaking it is best for these devices to be configured for g or b and disable the fancy feature which stomps on signals and acts like interference. They will do better not just you. Disable anything out of the ordinary.