I'd go for Yellow-bellied Elaenia on the first bird. Small headed / large eyed look of an Elaenia, the distinct teardrops on the wing bars, longer bird, dumpy body, longer tail, blanker facial expression with a more complete eye ring... maybe I'm missing something but my first impression screamed Elaenia and now I cannot unsee it. Happy to be corrected though if I'm out in the weeds on this one.