There are many ways to use your pants, coveralls, long sleeve shirt, hat etc for flotation. Water survivability is taught to every Marine or Sailor.
You could probably do the same with waiders. You can either scoop up air or splash it in. Here is a video but there are many methods. Sometimes for pants you can tie each leg off fill with air then stick the crotch area under your stomach. ..Essentially water wings. The video method may be good for waiders so the boot can rest behind your neck.
I wear boardshorts but my wife complains about the stink if I get bloody from a kill. Waiders probably repel the stink a lot better.
https://youtu.be/Fn80OMNrX4g