Clarifying question -- what do you mean Gollum was not yet a Hobbit? I don't think he ever was - but a river folk before the ring deprived him wasn't he? I never read first edition so I suspect there are some differences as you allude. (ring not being the ring).
Actually - in the creative process did he kick off the Hobbit then expand into the world building as an after thought and turn the one ring into this wild expansive creative endeavor? I always assumed it had been pre-built in his mind then spilled out in ink (As a sequence of events).
Gollum was retconned to be a hobbit after the illustrations were done.
Gollum was a river hobbit corrupted by the ring
In the original version, there is minimal physical description of Gollum (it was dark after all) and the ring was simply a magic ring that granted invisibility. Gollum lost it and IIRC he just let Bilbo go. They whole idea of him being some hobbit-like creature corrupted by the One Ring was not present at all. It was one of a series of fairy-tale adventures no more important than the trolls turning to stone. Bilbo needed a way to sneak around Smaug, so he found a magic ring.
It's doubtless still possible to find that version, I read it in an old country library that had it on the shelf since the 1950s.