Quick question: does the following part provide a little bit of friction for the towball or is it moving inside it completely freely when attached?

https://www.bricklink.com/v2/catalog/catalogitem.page?P=63082#T=C

That one's essentially freely moving.  Though there are 2 types of towball, smooth e.g. https://www.bricklink.com/v2/catalog/catalogitem.page?P=15456#T=P which is the intended partner for trailer hitches, and textured e.g. https://www.bricklink.com/v2/catalog/catalogitem.page?P=22890#T=P which is used for posable figures.  The textured ones have more friction but not enough to hold any weight.

If you put the ball in a pose where the mold lines touch the socket, it will also have a slight stick.  Looks like all of them are molded so the mold line is horizontal equator when the piece is studs-up, which avoids hitting this kind of socket if both pieces are facing up.

Edited January 5Jan 5 by Stereo

How about part 30396?

https://www.bricklink.com/v2/catalog/catalogitem.page?P=30396&idColor=11#T=C&C=11

Does the hook move completely freely inside it or is there a bit of friction?

3 hours ago, Corydoras said:

How about part 30396?

https://www.bricklink.com/v2/catalog/catalogitem.page?P=30396&idColor=11#T=C&C=11

Does the hook move completely freely inside it or is there a bit of friction?

That one is also loose (by design, to help the hook dangle realistically)

Thank you!