" you will already have completed my argument"?

1)Does "you will already have completed my argument" mean " you will already have completely understood my argument"?
2) Does "elders whom parents tell them to trust" mean "elders whom parents tell them to trust parents"?

Background info:

If I have done my softening-up work well, you will already have
completed my argument about child brains and religion. Natural
selection builds child brains with a tendency to believe whatever
their parents and tribal elders tell them. Such trusting obedience is
valuable for survival: the analogue of steering by the moon for a
moth. But the flip side of trusting obedience is slavish gullibility.
The inevitable by-product is vulnerability to infection by mind
viruses. For excellent reasons related to Darwinian survival, child
brains need to trust parents, and elders whom parents tell them to
trust. An automatic consequence is that the truster has no way of dis-
tinguishing good advice from bad. The child cannot know that 'Don't
paddle in the crocodile-infested Limpopo' is good advice but 'You