Most people avoid stuffed animals in the cage unsupervised, because there is top stitching on them like the eyes nose n mouth. On that particular stuffy, the long fur would get gross really fast.
I've never ever heard of a glider eating stuffing, I can't even imagine them being able to swallow any of it like a dog could. But they could get tangled up in it if they got enough of it pulled out. That is IF you have a glider that chews.
It would be cute for a brief supervised photo op tho.
There are glider safe bonding buddies that are safe to put in the cage, that are stuffed with fleece. They are awesome for single gliders, scent swapping before intros and just plain cute. https://www.facebook.com/CreatedMoments/?ref=br_rs