I fully expect that in Zeke's attempts in converting Eren, he himself would be converted.
And in his loss, Eren can just convince Zeke of a super solution that somehow fixes everything.
@ayechance in ch129, page 4, Ririsu has a flashback of Tarou telling her to be happy as her normal self. Her being normal can only mean to stop pretending to be a guy. If that isn't enough, page 5 also says "Tarou, Getting him to know I'm a girl, that's enough for me" just clarifies this. In...
I would imagine that Tarous dad's zombies came from other people, given that he's been chasing them for so long that he might have ended up becoming jealous not having one himself