On the first play is the PF against the offense or defense? If offense then you have to ask if it was a live ball or dead ball foul. If live ball then the penalty is enforced from the spot of the foul (All-but-one). If dead ball then enforced on the try or kickoff (B's choice). If defense than it doesn't matter if live or dead since enforcement is the same in this example. Try or kickoff.
One the second play this is a succeeding spot enforcement regardless of live/dead or location of the foul. The offended team can chose to have it enforced on the try or kickoff.