[Child of the 7th Age]

Although I instinctively prefer the Hobbit as we now have it with either the original or revised Riddles chapter, I would be curious to see the scraps of this grown up version. Tolkien gave up on that before the group reached Rivendell, so he obviously felt something wasn’t working.

Regarding how much and to what extent the Hobbit is tied to the Legendarium, I feel it’s not an “either/or” but "how much" and "when". Those same terms could even be applied to the LotR, although in the latter case it happened at some point during the initial composition/revisions.

Unless Rateliff has some evidence we’ve never seen or some way of slipping inside the author’s head, it would be extremely difficult to make an argument that in 1928-1932, when Tolkien told stories to his children, he consciously had a later age of the Legendarium in mind. If Rateliff could “prove” that point, it would turn a lot of accepted truths upside down. Still, the creation of the Hobbit was not confined to those few years, but was a gradual process beginning in 1928 (or before) and going all the way into the fifties when he did his Riddle revisions, possibly even to the sixties if you count the aborted “adult” revision none of us have seen. At some point in that lengthy creative process, the Hobbit was pulled in. My feeling, based on absolutely nothing other than instinct, says sooner rather than later. In that sense, the Hobbit was little different from LotR. In neither case did the author know from the beginning that he was dealing with the Legendarium. When he recognized what had happened to his hobbit sequel, he must have been acutely, even uncomfortably aware, of what this meant for the "original" tale.

As you mention, there is some early indication he was already thinking beyond the First Age. The origins of Aelfwine go back to a poem published in 1924, and Tolkien was definitely starting to think in terms of “later ages” with his work on Aelfwine, the Lost Road, and Numenor in 1936 (to some extent revisions of that earlier poem). This was the same time he worked on and submitted the maps for Hobbit. These were the ones showing the lands between the Misty Mountains and Mirkwood. I’ve always wondered if the whole process of both the LotR and the Hobbit both being pulled into the Legendarium wasn’t expressed through concrete geography, the problem of establishing a “mental map” of Middle Earth, as much as through abstract thinking. In any case, it will be interesting to see what he’s come up with and see how convincing it is. And I admit I am sympathetic and hope that I will not be disappointed!