I basically agree with your definitions. However:

Subjective properties that tend to make a creature seek something can only do that because those subjective properties correspond to some objective physical property, at least if you aren't supporting dualism.

Why do the subjective properties that, in fact, tend to make people seek such experiences, correspond to objective properties that lead to that particular physical result (i.e. tending to physically move toward those results.)

You can say this is a tautology, and it is, in a way. But if we are simply talking about the particular subjective property in itself (as opposed to the fact that we happen to be pointing to it using our tendency to seek it), it is not a tautology, even if it may be a physical necessity.

In other words: zombies are probably physically impossible. But if they were possible, and if they were actual, instead of real humans, then reality would be neutral, neither good nor evil, since there would be no experience. In a similar way, negative-humans (who tend to seek painful experiences and avoid pleasant ones) are likely physically impossible. But if they were possible and actual, then the universe would be evil, and nearly all experiences would be bad.

But as it is, most experiences are good, and the universe is good. Talking about God here is probably a distraction, but if the universe is good, then its cause or causes should also be good. If the facts that make the universe good are necessary, then its causes are necessarily good.