Those concepts are invented by TTN, they are not part of any existing specification (since LoRa does not really define anything for the internet side of things, we had to invent our own terminology and architecture).
No, the architecture has only recently been proposed, but still needs more work and evaluation (formal or informal). Also, our ideas need to written down in more detail as well, the current proposal presentation does not reflect all the things discussed in the design meeting.
There will be a provision for this, but we just haven't decided on the details of this yet.
Given that LoRaWAN pretty much only specifies the RF side of things, not the internet side, I don't think we're deviating from the standard at all. During the design, this was an explicit goal, to stick to the LoRaWAN specification completly, so any off-the-shelf LoRa devices will be able to work with TTN in the future.