Can you taboo "negative affect"? I was fine with it as shorthand when it was pointing vaguely to an illustrative subset of the space of emotions, but if you mean to define it as a sharp-edged boundary of what we can safely eliminate, it might be helpful to define it more clearly.

Depending on what you mean by the term, I might agree with you that "remove all negative affect" is too big a change.

Can you identify any positive preferences within yourself which do not correspond to a positive emotion?

Well, I feel the emotion of satisfaction when I'm aware of my preferences being satisfied, so a correspondence necessarily exists in those cases. In cases where I'm not aware of my preference being satisfied, I typically don't experience any differential emotion. E.g., given a choice between people not suffering and my being unaware of people suffering, I prefer the former, although I don't experience them differently (emotionally or any other way).