I Unfold Unto You a Mystery

I read this with the kids this week.  Alma's doctrine of revelation clearly comes from or informs the Worship of the Shalems.  He's unfolding a "mystery," he twice describes resurrection in the language of dressing, and he identifies it as something that doesn't happen until Christ comes.  This corresponds to the action in the Hekal, when the Lord-Melchizedek descends (Christ arrives) and dresses the initiates.

He Bringeth to Pass the Resurrection of the Dead

The resurrection is described in terms of the Worship of the Shalems: going up (one ascended into the temple) to stand before the judgment seat (the throne in the Holy of Holies upon the rock, where the Lord would reject some and admit others).

But universal resurrection happened on the Day of Atonement, Judgment Day.  I think this ambiguity is the source of the speculation Alma refers to, when he says that whether there's one resurrection or more, he doesn't know... notice that he refers to these things as "mysteries."