I can't recall which one it was, but I can remember seeing one of my snakes appearing to have hiccups for a little while, & nothing came of it, so I'd
say just wait & see for a while. I don't think snake's have a diaphragm (of which hiccups are an involuntary spasm) and they cannot cough either,
but I suppose something else could mimic that? (they can, for example, pass gas) I don't think it's a sign of an RI. It's unusual for a snake to yawn
while out of their cage too...maybe she needs "burped"?(good question! I hope someone else will chime in too?) How long have you observed
these "hiccups", by the way???