So Marchesa, the Black Rose has the following ability:

Whenever a creature you control with a +1/+1 counter on it dies, return that card to the battlefield under your control at the beginning of the next end step.

In a game today, I had a number of creatures, including Marchesa herself, sitting happily with one or more +1/+1 counters on them when Anger of the Gods followed by Fork was played, dealing 6 damage to each creature on the board. This was sufficient to kill most of my creatures despite their +1/+1's.

^{It dawns on me that even if Marchesa's ability would trigger, Anger of the Gods exiling things would prevent it from working; for the purposes of this question, ignore that.}

So, the question is, when Marchesa and several other creatures would be killed simultaneously,

1. Does Marchesa's ability trigger for herself?

2. Does Marchesa's ability trigger for the other creatures under my control with +1/+1 counters?

In attempting to resolve the issue, we tried to look things up, leading to this forum post, which cites Rule 603.6d as proving that Marchesa's ability should trigger both for herself and for each other creature with +1/+1 counters.

Unfortunately, none of us could actually understand Rule 603.6d, aside from this example:

Two creatures are on the battlefield along with an artifact that has the ability Whenever a creature dies, you gain 1 life. Someone plays a spell that destroys all artifacts, creatures, and enchantments. The artifacts ability triggers twice, even though the artifact goes to its owners graveyard at the same time as the creatures.

The example certainly seems analogous to me (though the source of the Anger of the Gods argued that it's different as an Artifact ability rather than a Creature ability for some reason), but without understanding the actual rule, rather than just the example, we weren't too sure.

So a complete answer has to not only answer the question, but back up that answer with citation and explanation of the official rules on the matter.

^{For the record, we wound up deciding it with a coin toss, which I won. I still lost the game; Rhys the Redeemer got about forty tokens in about two turns while everyone else had almost-nothing after the Angers of the Gods and some other "Bury all nonland permanents" card were played.}