Is there a possibility of turning URL-LS into an IETF RFC?
Publishing URL-LS content under an IETF RFC may be possible, but doing so wouldn't cause the the URL-LS effort to be abandoned, which would require evidence that the IETF spec is better maintained than the WHATWG effort. There is precedent for this, the WHATWG abandoned effort on a DOM related specification (events?) after it became clear that the W3C version was more actively maintained.