Interference on foul fly ball ?

[playball13]

Similar setup pop-up foul about 7 feet behind 1B. R1 and F3 collide.
However F4 calls the ball and catches ball in foul territory.
The pop-up could have been caught be either player.
Let's assume F3 chance for catch is NOT ordinary effort but catchable, F4 chance for the catch is easier.

Is this still interference even though F3 did not catch the ball?
Is this a double play R1 out for interference and BR out for caught fly ball?
Is this all about who had the best chance to catch to make the play?

[MTR]

Similar setup pop-up foul about 7 feet behind 1B. R1 and F3 collide.
However F4 calls the ball and catches ball in foul territory.
The pop-up could have been caught be either player.
Let's assume F3 chance for catch is NOT ordinary effort but catchable, F4 chance for the catch is easier.

Is this still interference even though F3 did not catch the ball?

Never happened, officially, since it is a dead ball at the moment of the INT. Whether it is INT or not depends on whether the umpire judged that F3 was the primary defender which was most likely to be the one to catch the ball prior to the INT.

Is this a double play R1 out for interference and BR out for caught fly ball?

Only if it was deemed that F3 would have caught the ball with ordinary effort. From the sounds of the play, that may not be the case.

Is this all about who had the best chance to catch to make the play?

Yes

[Patrick]

Why was R1 seven feet behind first base in foul territory?

[GIMNEPIWO]

Why was R1 seven feet behind first base in foul territory?

Maybe she was coming back from the bathroom ...