Legate of Ammon Lanc well points out where the answers to three of TheLostPilgrim’s questions may be found.
As to the question of whether Sméagol was a Hobbit, Gandalf in his explanation of Sméagol’s origin says:
Long after, but still very long ago, there lived by the banks of the Great River on the edge of Wilderland a clever-handed and quiet-footed little people. I guess they were of hobbit-kind; akin to the fathers of the fathers of the Stoors, for they loved the River, and often swam in it, or made little boats of reeds.
Gandalf is represented here as being somewhat pedantic in his choice of words. Earlier when asked by Frodo how long Gandalf has known what he has related about the Ring, Tolkien gives to Gandalf this reply:
‘Known?’ said Gandalf. ‘I have known much that only the Wise know, Frodo, But if you mean “known about this ring”, well I still do not know, one might say. There is a last test to make. But I no longer doubt my guess.’
Similarly there is no reason to think that Gandalf doubts his guess about Sméagol’s origin. Of course the possibility exists that Sméagol might be of Orkish kindred, or even possibly of another branch of hobitkind than the Stoors, but of a clan who, though not closely related to the Stoors, had developed customs in respect to swimming and boating similar to the later Stoors.
Whether Sméagol thought of himself as a
hobbit is doubtful. In Appendix F Tolkien writes:
The origin of the word hobbit was by most forgotten. It seems, however to have been at first a name given to the Harfoots by the Fallohides and Stoors, and to be a worn-down form of a word preserved more fully in Rohan: holbytla ‘hole-builder’.
Sméagol might have thought of himself primarily as a Stoor or a Halfling, Halfling being the normal English version of the true Westron name used for all the folk that were later came to be called
hobbits in the Shire and in Buckland and in Breeland.