Thanks for taking the time to reply. I love these bird ID challenges.
I ruled out Bridled for the same reason you say, the two species are only an inch apart. I actually considered the perspective issue before posting here to POTN, especially because I agree it looks like a Sooty.
I did not think it was a perspective issue, however, because all three birds look close to each other. Just as close as the two large ones on the right. That's why I wondered if it might be a Least Tern (didn't really see a yellow bill though) or maybe a juvy Sooty.
I ended up throwing the question to POTN as I just had one day to see these birds and habitat. So I was hoping someone more familiar with sea terns would weigh in.
Thanks again for the comments.