Federation is planned, but there are still behaviors of atproto that are as of yet undefined, and need to be defined and ironed out before Bluesky's primary network is open to federation.
As for your second question, I don't think any "last number" could exist unless we explicitly declared one. And even then... I'm not sure what utility there would be in declaring a "last number".
Maybe it's like vacuum decay; yes, it's already happened, but maybe it doesn't propagate instantly. There are expanding pockets of dead universes around where malfunctions occurred, but the Multiverse, in its infinite size, means that these pockets are also infinitesimally small compared to it.
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