The bottom bird looks more like a Pine Warbler to me. Overall shape seems more warbler like and the bill is all dark, Yellow-throated Vireo should have a slightly lighter colour to the base of the bottom part of the bill. The bill seems a little too slim as well. Also, the back pattern seems to stark. Pine Warbler has a clean-cut look between the yellow back and grey wings while on a Yellow-throated Vireo the yellow seems to almost blend into the grey in the wings.
I hope this helps,
Jax