Checking the tag definition for gender change shows a specific exclusion of female→herm, implying that male→herm should get the tag. Note that reptilian/draconic anthros are not always portrayed with mammaries, (as those are technically mammalian specific).
No, it doesn't. In fact "A female becoming a futanari does not qualify" implies the exact opposite of that. If a female character gaining a dick in addition to her pussy doesn't count as changing gender, then neither should a man gaining a pussy in addition to his dick. It's the logical conclusion of that definition.