The reunion of body and soul begins with the resurrection of the Messiah, but Alma still doesn’t understand whether all who have died by the time of the Messiah’s resurrection will be resurrected at that same time, or if there will be some whose length of time between death and resurrection would be extended, while others had already begun to be resurrected. Alma says that he believes that those who are righteous will be resurrected at that time, but “whether it be at his resurrection or after, [he does] not say.”
Regardless of the timing, however, there is a space between temporal death and the resurrection, and there will be a time after the resurrection when the reunited soul and body are brought to stand before God to be judged and assigned to a final state.