Can we also define this kind of ought naturalistically? I think that we can, because once again I deny that "wrong" has any prior metaphysical meaning. The trick is to make the new (by definition) meaning not clash too harshly with the existing metaphysical connotations

The main trick seems to be getting people to agree on a definition. For instance this:.

How is this for a first attempt at a naturalistic definition of the moral ought as a subset of the practical ought? An agent morally ought not to do something iff it tends to generate consequences contrary to the agent's interests, those negative consequences arising from the reactions of disapproval coming from other agents.

...aims rather low. That just tells people to do what they would do anyway. Part of the social function of morality is to give people an ideal to personally aim towards. Another part of the social function of morality is to provide people with an ideal form of behaviour, in order to manipulate others into behaving "better". Another part of the social function of morality is to allow people to signal their goodness by broadcasting their moral code. Done right, that makes them seem more trustworthy and predictable. Your proposal does not score very well on these fronts.