Ngl, there was a time I would have assumed what is called a femboy was gay, trans, or otherwise tried to place a label on them in my head for ease of thinking.
Again, being real, I did do that, it's just that the people may not have been femboys, I'm kinda looking in the rear view mirror here. Back before a few years ago, the femboy term and general style trends that seem to be in use weren't anything I had run into much at all, and only online.
But, yeah, you gotta be real careful appling labels to people even in your own head, and you sure as fuck don't come out and apply those labels out loud, even in the form of a question.