1) It is possible to keep the whole site offline. A database from 2017 is 9 GB: https://archive.org/details/hackernews-2017-05-18.db I think a 2020 DB could be less than 20 GB.
2) My focus is on reading, not writing. Local favorites make sense. Maybe with importing public favorites. A user can set their name without logging in.
3/4) SQLite does the heavy lifting here.
