In your first example, because there was no Virtual Certainty that the original ball was in the hazard, the player was not authorized to play from the drop zone. In doing so he played using an inapplicable rule. (R26-1 Relief from Ball in Water Hazard). The only applicable rule that would apply with what he did was R27-1 Stroke and Distance. However, when he dropped in the drop zone he dropped in a wrong place. R27 requires you to play from the previous spot. When he played the dropped ball he incurred a 2 stroke penalty for playing from an wrong place as well as a 1 stroke penalty under R27.
Now, when he abandoned this ball and played his original, he played a wrong ball because that ball was no longer in play. The first thing to decide is whether or not the player, when playing the ball from the drop zone, committed a serious breach. A serious breach is when a player gains a significant advantage from playing from a wrong place. (Wrong Place R20-7) In this case he played from a drop zone vs. the previous spot back on the tee which he should have under R27, so I'm guessing it was a serious breach. In that case he was required to correct by playing from the correct spot before he teed off from the next hole. The correct spot is back on the tee under rule 27.
So he should have went back to the tee playing his 5th stroke. ( His original stroke, plus 3 penalty strokes.) If he teed off on the next hole without doing this, he is DQ'd. I believe he's off the hook for the wrong ball penalty because it occurred after he played form the Wrong Place with a serious breach.
If there was no serious breach committed from playing from the wrong place, he would have to correct the error for playing the wrong ball. (He abandoned his ball played from the drop zone, when he should not have.) So before he teed off on the next hole, he would have had to go back and continue play from where his ball ended up from his stroke from the drop zone,adding 5 PS to his score. 2 for the Wrong ball and 2 for the Wrong Place, and 1 under R27.
This one was interesting, Let me know if I have it wrong. The thing I'm not sure is the 2PS for the wrong ball if the player played from the wrong place and it was a serious breach. Normally, when you have to correct, any penalty strokes incurred after playing from the wrong place do not count.