How does the serverless driver and connection pooling impact pricing? Will it keep instances active and hence run for all of the month?

No, the compute shuts down on inactivity in 5 minutes regardless of active connections.

AWS released Aurora I/O-Optimized that for a higher storage cost no longer charges for I/O (quoted 40% savings).

Is such a mode being considered for Neon? If not, will there be future adjustments in pricing?

I see you support timescaledb extension.

How does that work? Is a "chunk" in timescaledb split into "pages" and just streamed from S3?

Neon works at the storage level: https://neon.tech/docs/introduction/architecture-overview

So all extensions including Timescale work. Postgres does the heavy lifting

Does this affect ACID guarantees at all? Could Postgres ever expect to read back a page with currently-changing data from the Pageserver before those changes get propagated there? Will the Pageserver cluster block I/O if it’s waiting on a page to reach a consistent state?

Neon is as consistent as Postgres. B/c it's Postgres. All we did was swapping storage.