It's an issue of arete (loosely, "virtue") and the effects of devoutly and completely adhering to it in human life. Achilles seems extreme to us because he's the embodiment of a pagan ideal which may seem more familiar if considering the Christian counterpart in (excuse the comparison) Christ, who suffered whatever he had to suffer for his total piety (a christian parallel of sorts to arete).
>in the Odyssey he is someone to admire
Arguable. His shifty nature is, if not outright scorned, at least disputed for its worth in a culture at least purporting to be based in honor. See the very tongue in cheek "praise" of Odysseus in Plato's "Hippias Minor," which elicits horror from Socrates' listeners when he suggests Odysseus might be a match for Achilles.
>Achilles in the Iliad is not somebody to admire
Absolutely wrong. He's the perfect embodiment of arete, of winning glory at the sacrifice of life, of virtue over convenience, etc.
>Heracles
You're kind of right. Remember that of the great Greek heroes (Heracles, Theseus), Heracles is still the "strong" one and Theseus the "smart" one. Also note how much more attention Heracles gets in comparison with Theseus.
>In short, Homer is providing (and very likely reflecting) moral values through them being personified.
This is correct. Your interpretations of the personalities are a bit rusty, but you definitely have the right idea.
>Zeus
As an interesting aside, Zeus DID fear overthrow, but a strong son was just a symptom of more general Fate, which rules even the (hardly permanently empowered) gods, according to Aeschylus (prometheus bound: "Do you think I will crouch before your Gods,—so new—and tremble?")
>Who then is the steersman of necessity?
>The triple-formed Fates and the remembering Furies.
>Is Zeus weaker than these?
>Yes, for he, too, cannot escape what is fated.
You're right about Achilles being praised for his actions, but I'm not sure it's for his kindness to Priam. Maybe that's why Zeus honored Achilles, but was it the honor of Zeus or men that Achilles sought at Troy? He knew he would die in exchange for eternal fame, but fame in whose eyes?
>the Iliad ,may be a bit too much for a seven year old.
>not learning homeric greek to read it to your infant son
>not starting your kids with the greeks