Butters, the ball python I got as a x-mas gift to my youngest was finishing up a patchy shed when we got him but was in great overall health. After a warm damp cloth to clean up the last of the dry shed he was great. The next day I took him out to clean and fluff his tub I noticed a slight whistle when he was exhaling. And it seemed to be labored. I consider myself a newbie and that means I know enough to get me in trouble. I started to panic thinking RI...do I get him away from my other snakes room for safety did I get him sick somehow? I started to inspect him and look for signs of a RI that I read here, and guess what I little pice of dry scale was stuck in his nostril, when it was damp it didn't make any noise but after it dried it made him whistle and I believe the labored part of his exhale was just his with of tring to blow his nose I guess cause that stopped as well after I removed the obstruction
Some of my garters will pop, click, and even gape right before a shed (usually this is when their tongues shed but are still stuck in their mouths). Best imitation of an RI that you've ever seen. My BP will sometimes whistle a little but so far she hasn't made me think 'RI' yet.
Colubrids do. It's the weirdest thing; I usually see the tongue shed up to a day or two before the whole body shed. Not 100% sure whether pythons do or not now that you ask. I guess I just kind of assumed they do.