Player Control or Block

[regs1234]

Play 1:

(a) A1 catches a pass in mid-air and B1 slides into a spot while A1 is in the air and there is a crash as A1 lands.

This would be a block correct bc B1 was not there before A1 elited?

(b) A1 catches a pass in mid-air with his back to B1 and B1 had already established this position before A1 elited, there is a crash as A1 lands.

Player control foul?

Play2:

A1 catches a pass with both feet on the ground, elites into a jump stop. As A1 elites on jump stop B1 (who had legal guarding positon before A1 elited) moves forward into the space that A1 is jumping into. Upon landing A1 and
B1 crash.

Block because B1 moved into this positon while A1 was in the air?

Please respond. Thanks.