Hi Jonathan
Delayed reply because your message just made it to my inbox.  I hate to burst your bubble but this bird looks good for a young Warbling Vireo (which are the brightest/most contrasty version of this species that we see because they’re in fresh plumage July to September whereas adults arrive in May & leave by August in quite worn/ faded plumage) and here are several reasons:

– the eye-line isn’t black enough – on Philadelphia, it should be darker than the cap, and distinctly dark in front of the eye
– the chest isn’t yellow enough – in particular, Philadelphia should be brightest on the center of the chest whereas this bird seems equally yellowish-white, or maybe the flanks are subtly brighter
– beak too long (though this one is hard to judge & I wouldn’t rely solely on this)
– and, for the finer details, on your image #1 you can actually make out the reduced primary 10 (barely longer than the primary coverts) as it slightly hangs down from the folded wing – this is a feather that Warbling has and Philadelphia lacks
You are far the from the first person to jump at a fresh late summer/fall Warbling … and I was a bit tempted when I saw the thumbnail shots pop up, including one view (image #3) which suggests a shorter tail (though image #1 shows that the tail isn’t so short).
I hope this helps/makes sense,
Jay