Sorry for the late response.
I suppose it's up to you how to handle turns. That is a movement that usually needs to be instant, else your controls will feel sluggish to the user. That's similar to going from idle to walk/run or back to idle
it can't take too long because the user expects their character to react to their inputs quickly.
For turnaround, most games do it instantly. You could do that, then play an animation that is the turnaround. In some Super Mario games, Nintendo does this if Mario is running quickly, he faces the other way instantly but has a sliding animation. They also have a little puff VFX at his feet, IIRC.
Turnaround is likely to be somewhat of a jerky movement, especially if your character sticks out farther on one side. You could flip your skeleton instantly and play your turnaround, but have your turnaround animation start flipped. That way your character is facing the right direction as far as your controls and game logic are concerned, but the visual from the turnaround animation makes it take some time. I would still only use a couple frames to complete the turnaround animation.
Regarding your #1, I guess you are looking for Skeleton