Can I claim any sort of EV/Clean Energy Vehicle credit (in California) if I'm leasing the vehicle (did not purchase outright)?

You are not the owner of the vehicle since it is being leased so you are not eligible for any EV credit.

The Clean Vehicle Rebate Project (CVRP) is closed, effective November 8, 2023.

CVRP offered vehicle rebates on a first-come, first-served basis.