Why is Biden included in this poll and not Sanders? From this list, I'd go with Warren, obviously, followed by Brown. All of the others listed are absolutely atrocious but I'd support them if they won the nomination.
Newsom will become the next Governor of California about a year and a half from now. After being governor for roughly a year he will announce his run for the presidency. He will win over progressive voters that backed Sanders so strongly in 2016, largely due to his strong progressive support on key issues such as the environment, gay marriage, and marijuana legalization. He will win over enough of the remaining Dems to capture the party's nomination (aged 52), and will go on to win the presidency (aged 53) only two years after being elected Governor of California. Don't underestimate Newsom. He's the one to watch. Pay attention.
You realize that we're in 2017, right? No one cares about Newsom's record on gay marriage.
All California democrats have a strong record on gay rights/marriage it would be political sucicide not to.