Although I haven't found any confirmation of this, the fact that the NPC Eruaran has the appearance of an elf could perhaps be confirmation of this. In fact, the NPC reacts to the word Teshial in this way:
Eruaran: That's only a word. Words are rough and imprecise. If you'd walk the dreams for a while things would become far more clear because they are lost in obscurity. ...
Eruaran: I'm a living dream, rider of nightmares, wanderer in paradises and hells. I have seen wonders beyond compare. I experienced things an untrained mind could not only grasp. I am what I am.
Are there other facts that could prove this? Perhaps some book or speech from another NPC that could provide more clues about this?