Fantastic series, Scott. The Redstart is my favorite, but it's simply amazing to get this many varieties of warblers in one shot.
Just looking at my Sibley's, I would probably guess Palm Warbler on the one with the rufous crown. On the orange-crowned warbler, a note is made that the orange crown is rarely seen in the field. On either one, the range is correct.
On the other one, have you considered the possibility of a fledgling? I can't confirm it with a guide, but this guy looks just like the Eastern Phoebes that took off from their nest on our front porch about two weeks ago, although I can't say whether they had the little black mark (Although Sibley's does show a "smudge" at that point on a juvenile Eastern Phoebe.)
Remember, I'm often wrong.