I forgot about A Life - good cal, Kad. So my money is on Oslo, Sweat, Indecent and possibly A Life (I wasn't as crazy about The Wolves). Dear Evan Hansen, while a good musical, isn't nearly as solid dramaturgically as any of those others, and respectfully (while fully deserving to be in the running for Best Musical awards), doesn't belong in Pulitzer consideration. (Frankly, I wouldn't be surprised to see a nomination for Come From Away holding more ground as a hypothetical runner-up). But I'd still hope for Oslo.
As far as this business about it being ineligible because it's not about American life, I don't know that that's necessarily true. In the last 10 years alone, Bengal Tiger in the Baghdad Zoo was a runner up (set in Iraq), and most notably, 2009 Pulitzer winner Ruined, by the playwright of Sweat, took place entirely in the Democratic Republic of Congo. I think it's stated that the play 'preferably' or 'ideally' have to do with American life... but I'd argue the thematic implications of Oslo (the hope for peace) have more overall bearing on contemporary American life than even those of Ruined, as great a play as that is.
If Lynn Nottage and Paula Vogel hadn't both already won Pulitzers (and for what I think are stronger plays), I'd say it would be a three-horse-race - and Sweat would likely nab it for capturing something of the mood of the moment. But Sweat has problems - minor, but problems nonetheless - and Oslo is a sensationally enlightening and entertaining play by a well-regarded playwright (who as yet has not achieved a slew of awards recognition), and is a profound work with a true uplifting message of hope. I'm sure neither Vogel nor Nottage would say no to a second Pulitzer, but I bet even they wouldn't be surprised to see it going to JT Rogers this time around. We'll see.
(Maybe this'll be one of those years the committee decides that no play merits the award - can you imagine??)