1) Rule 3.05b: Yes. A substitution is proper if the pitcher "makes his first pitch to the batter,
or as soon as any runner is put out."
2) Rule 7.04c: After the catch, the ball is dead and runners advance one base without a
chance of being put out.
3) Rules 3.15: Since the photographer was authorized and the interference was
unintentional, the ball is alive and in play.