Although it will not answer all the questions posed, there is available a recent publication entitled "History of O Scale" or something like that for $20 + tax + shipping, etc as appropriate.
Note : probably not for 3 rail folks looking for something about Lionel. This publication is focused on 2 rail and names like Mi-Loco, Lobaugh, Megow, General Models, USH, Kemtron, and many others not known in the 3 rail community.