Double First Base situation

[Big_Mike]

NYSSO/ASA

In a recent game on a bunt play F3 charged the bunt. F5 fielded the ball and threw to 1st base. On the play the F4 covering 1st base set up on the orange side. The throw came right to her as she was set up on orange. The batter runner as she approached the bag saw the fielder on the orange base and slowed down to avoid a crash. She was thrown out on the play and the official ruled that the defense can use either portion as the throw came to the orange base. The batter runner did not go to the white portion but tried to avoid the collision and slowed down.

Questions:

Can F4 set up on either portion if the ball is coming from fair territory?

(Obviously, if the throw takes her to orange, she can use that portion)

Can we have obstruction on the defense (F4)?

Mike