Abbayai over there answers that those three cases, the reason why he’s not choshid is because we’re chayish for sofek malve yeshana. And, if not for that, we’d say choshid amomoina choshid ashvuasa.
Your kasha was Tosefus. My asnser is Ramban.
P’nei Yehoshua defends Tosefus: if we’re always chayish for sofek malve yeshana, then the bottom line is he can never be choshid ashvuasa.