Let's be real honest here. The Dems have gone 100% in on identity politics. As such, there is no way that they are nominating a man for president in 2020. So Chuck Schumer, Joe Biden, Andrew Cuomo, Gore, Shultz, Gavin Newsom, etc can just stop trying now. Now, what is unknown is exactly how many check boxes the person needs to check before they are seriously considered. I think Beto is a non-starter, too white. As for women, I think Warren is also eliminated by the "too much of an old white lady" view of the dem base. Hillary will be fighting this too and she is the only one that has enough cash to potentially pull it off.
But, we know the dem dream candidate - they want 1.) Female, 2.) Under-represented minority, 3.) preferably famous for reasons outside politics because their voter base is too ignorant to understand policy implications. So, we have 2 really good people to pick from and a 3rd as a long shot. I think the dem nomination will be fought over by:
Oprah would actually stand a chance against Trump despite have zero political experience. She is too established as a loved personality in the US for Trump to effectively demonize. Michelle will be even more polarizing that Hillary with her politics experience solely the result of sleeping with Barry. But, I suspect all those Dems laughing at Trump because he lacked prior experience will suddenly find that to be a virtue. As for Harris, sleeping with Willie Brown made her what she is today by earning her place in the CA democrat machine. Unfortunately, she really is not that likeable and has nothing to show for all her years in politics.
Lastly, I doubt O'Crazio-Cortez will ever be big in the Dem party. My bet is that she says or does something so incredibly stupid that she disqualifies herself from a leadership position. She will likely keep getting re-elected though. People in NYC as pretty stupid that way as seen with Barney Frank.