Right Enforcement?

[gtwbam]

Indeed the score does count.

And A does have the option of enforcing B's foul on the try or the kickoff.

However B's options for enforcement on the unsportsmanship conduct by A will apply to both the try and succeeding kickoff as well

The options given to B on the unsportsmanlike conduct penalty by A is not determined whether the player crossed the goal line, its determined by when it occurred, whether it was before or after the ready-for-play whistle for the try. In this case its before.