Air is only blowing through my defrost vents

This is most likely the mode door actuator. This is the actuator is responsible for moving the door that directs the air to different vents.

I attached the process for changing this out. As for the fuzzy pieces, that could be a number of things. It could be the foam that is on the doors to soften the sound when the reach the stopping points. It could be stuff that a mouse put in there as well so it is hard to say. Can you get a picture of it and we will try to identify it.

Let me know if you have questions. Thanks