The legislature has until March 3rd to override any of Newsom's current batch of vetos (60 days after reconving on January 3rd, 2024). The legislature may also override a veto of a bill passed later, which is why this question ends at the start of spring recess, which I believe is March 21st, 2024 (I will updated the question title/description if I'm wrong).
http://www.leginfo.ca.gov/rules/joint_rules.pdf
https://www.assembly.ca.gov/schedules-publications/legislative-deadlines

The California legislature has not overriden a veto since the 1979/1980 session.
https://www.latimes.com/california/newsletter/2021-10-15/california-politics-governor-all-powerful-veto-ca-politics

A bill being modified, re-passed, and signed does not count as overriding a veto.