4/5 does at least two significant changes besides removing the field. Those two changes should be split, and it wouldn't even be amiss to remove the field in a third commit after it has no users. (Assuming that we can even remove the field, though; see my inline comment.)
5/5 could use a better subject. Not only is "introduce a new function" incomplete (since the function is also *used* in the same commmit), but it doesn't tell me what code it's replacing. Nor does it explain why. Why is this separate entry point better?