Determine Pivot foot after ending dribble

[potato]

Just like to make sure how pivot foot is established. Especially when a player is on the move & ends his dribble.

1.Player catches the ball with one foot (left) on the floor:
a.if the other foot touches the floor so both feet are on the floor, the left foot is the pivot.
b.if the other foot (right) touches the floor while the left foot is lifted, the right foot is the pivot.

2.Player catches the ball with both foot on the floor:
Either 1 of the feet can be chosen as pivot

3.Player catches the ball with no foot on the floor,
a.the 1st foot that touches the floor is the pivot,
b.both feet land at the same time player can choose 1 pivot foot.

I hope the above scenarios are correct.

But i have a 4th scenario:

4.Player catches the ball with 1 foot on the floor (left), stands on that foot, does a few pump fakes for few seconds, then steps on his other foot (right) while his left foot leaves the floor, this scenario is similar to 1 except the player stopped for a while before continuing with his 2nd step, so would the right foot be his pivot or his left?

Must the player catch the ball with 1 foot already on the ground to make the 2nd foot a pivot or the player can catch the ball with 1 foot touching the floor simultaneously?