Alright so here is where the timeline of no.0 gets a bit confusing to me. Tatsuki was the leader from when Kyara died, but here he's already no.0, so I think he was 0 when his father was leader?
Then the order would be
Tatsuki -> Kyara -> Souji -> Tatsuki (Kyara quit) -> Yakou (?)
The age gap is also a little weird. Nowa said Tatsuki always looked younger than his age and he aged backwards after returning to his referee position, so how old should he be in actuality? 70?