I don't think those questions are mere stand-ins. I think the answers to "does X deserve legal consideration?" or "does X deserve moral consideration?" depend heavily on "Is X conscious?" and "Does X experience pain/pleasure?" That is, if we answer "Is X conscious?" and "Does X experience pain/pleasure?" then we can answer "does X deserve legal consideration?" and "does X deserve moral consideration?"

If "Is X conscious?" and "Does X experience pain/pleasure?" simply stand-ins for "does X deserve legal consideration?" or "does X deserve moral consideration?", then if we answered the latter two we'd stop caring about the former. I don't think that's so. There are still very interesting, very deep scientific questions to be answered about just what it means when we say something is conscious.

The problem is that I, for one, don't know what the question "Is X conscious?" means and I'm not sure how to judge "Does X experience pain/pleasure?" in a non-biological context either. Nor has anyone else ever convinced me they know the answers to these questions. Still, it does seem as if neurobiology is making slow progress on these questions so they're probably not intractable or meaningless. When all is said and done, they may not mean exactly what we vaguely feel they mean today; but I suspect that "conscious" will be more like the concept of "atom" than the concept of "ether". I.e. we'll recognize a clear connection between the original use of the word and the much more refined and detailed understanding we eventually come to. On the other hand, I could be wrong about that; and consciousness could turn out to be as useless a concept as ether or phlogiston.