There are some possibilities that you missed. This one, for example:
* God is a good experimentalist, and like all good experimentalists, he rarely intervenes with the way things play out in his creation/experimental system. He sits back and passively observes, for hundreds or thousands of years at a time, and Jesus is the product of "Ok, I'm tired of the dynamic that the most intelligent carbon units have gotten into; let's see what happens if I have one of them teach some ethical principles to the others."
I didn't miss it, because this is an inconsistent possibility (not that it is possible to come up with a coherent and consistent theory of God, but that's a REALLY long discussion) Let's see. How could God be a good experimentalist? Well we usually perform experiments to learn something where we don't know the outcome. But God is omniscient, and cannot NOT know the outcome (and remain God), at least not unless you want to become a Hindu monist pandeist and imagine Mahavishnu/Brahma splitting its omniscient universal self (Brahman) into all of the many sparks of life (Atman) that have forgotten the perfect knowledge of Brahman. However, this view is generally opposed by most Abrahamic theologists because it destroys the essential dualism required to have a God to worship who can punish and reward and make the whole system work (not to mention that it contradicts pretty much all of the sacred texts of the family of religions).
Now, God could also be an experimentalist by playing dice with the Universe -- just rolling out a big, unknown Universe with no idea how it will all come out, a big reality simulation, just to see what happens, and then he could sit there blaming the lifeforms that emerge for being precisely what the dice he used plus the ruleset he used produced and invent ANOTHER pair of realities, one in which those lifeforms can live forever being tortured by demonic merciless robots, one in which those lifeforms can all sit around and chant praises for eternity to make him feel Really Important. But I hope that we agree that this is a rather ugly picture of God as well.
Besides, you're contradicting a number of essential statements from the Gospels, notably John, and your comment stinks of the Arian heresy that was stamped out post Nicaea (with fire and steel). Jesus is the alpha and omega, dude, and was there at the beginning and will be there at the end. So God cannot decide to send us Jesus to teach us ethical principles because there is no real difference between Jesus and God. Jesus/God sent himself, as he knew he would at the beginning, to produce precisely the outcome he predestined at the end. If you are damned, you have no choice in the matter as you were damned from the beginning of time. Not that the Gospels are consistent on this point. But let's have a look:
Mark 4:11 And he said unto them, Unto you it is given to know the mystery of the kingdom of God: but unto them that are without, all these things are done in parables:
4:12 That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them.
Mark 10:18 And Jesus said unto him, Why callest thou me good? there is none good but one, that is, God.
Matthew: 11:25 At that time Jesus answered and said, I thank thee, O Father, Lord of heaven and earth, because thou hast hid these things from the wise and prudent, and hast revealed them unto babes.
So, apparently, Jesus and God are different, Jesus is not God and doesn't even claim to be good! He deliberately teaches those predestined to be saved in parables so that ordinary people won't get it and WON'T be converted and saved. Thanks, Jesus! I'll adopt his methods in my physics class, I guess, and teach physics using metaphors instead of equations just so I can flunk all of the students I confuse. Hey, it's OK! It was predestined! But it is Matthew that directly contradicts your assertion. God has come up with a scheme that he hides from the wise and prudent and reveals only to the young who are stupid and foolish!
You might think about this (this is hardly the only time this is stated in the NT). Even at that time, Christianity made no real progress with people who weren't idiots, because even 2000 years ago, sensible people could recognize a charlatan when they saw one. Look earlier in this same chapter! Not even John the Baptist, who supposedly baptized Jesus to the accompaniment of many miracles, is certain Jesus is the messiah -- he doubts it from inside his prison cell as he supposedly awaits execution! But not to worry! Jesus proves it by rubbing spit in a blind man's eye:
Mark 8:23 And he took the blind man by the hand, and led him out of the town; and when he had spit on his eyes, and put his hands upon him, he asked him if he saw ought.
or was it mud, made with spit?
John 9:6 When he had thus spoken, he spat on the ground, and made clay of the spittle, and he anointed the eyes of the blind man with the clay,
9:7 And said unto him, Go, wash in the pool of Siloam, (which is by interpretation, Sent.) He went his way therefore, and washed, and came seeing.
This, apparently is a record of how Jesus cured things like blindness. With spit and dirt from the ground in a country where all non-foot transportation is provided by animals and where there is nothing like a sewer system or sanitation, dirt that has been urinated on and shat upon by animal and human alike since time immemorial. The mouth, you might recall, is literally the dirtiest part of the human body as far as dangerous bacteria are concerned. But not holy spit! That cures anything!
Interestingly, this story is in both a synoptic and in John. If you take the gospels seriously, that makes it rather more likely that this is an authentic account of how Jesus worked his magic in the crowd -- take the person out of town (away from the crowd), "heal them" with a show of traditional magic (because it certainly wasn't medicine) where only a few people could see, and then let the rumor spread. This is how he tried to convince John the Baptist that he really was the messiah over his apparent doubts. And since just a bit further down, he disparages John to the crowd and makes himself and his listeners out to be much greater (if they follow him) it doesn't take much imagination to think that just maybe he was trying to replace John and take over John's disciples and followers.
You can go to many third world countries and watch witch doctors work exactly this kind of "miracle" today. They even still frequently use, and used in the past, spit:
(see e.g. page 229). Holy spit isn't limited just to Jesus:
or even only to humans:
Holy Horse Spit! Or if you are willing to "believe", you can join a contemporary cult that uses this sort of technique:
Oh, wait, SGI doesn't do this. This was used as the archetype of cult fake medicine.
But I could do this all day. If you simply applied precisely the same common sense to Christianity and its scriptures and claims that you have absolutely no problem applying to Hinduism, Shamanism, the Great Spirit, Islam and Muhammed, Mormonism, Jehovah's Witnesses, Heaven's Gate, and so on you would not conclude that sending Jesus to the Earth to model healing techniques based on rubbing muddy spit into the human eye is an ethically defensible practice for an omniscient omnibenevolent being. You would also just possibly have to face up to the true magnitude of the problem of theodicy.
Finally, Jesus is hardly the first, or the best, of humans who have supposedly taught ethical behavior to carbon life forms. The teachings of the New Testament, looked at objectively, fall far short of a perfect ethos for human existence, with or without the God component. And yes, I can quote the NT all day on the issue because, unlike most "believers", I've actually read the damned thing, multiple times, especially the Gospels. As well as a lot of the OT (I get bored too quickly to properly finish it). As well as the Quran, the Upanishads, the Puranas, the Mahabharata, the Ramayana, the Book of Mormon. I would strongly recommend reading it, carefully, and asking yourself "is this the consistent record of anything LIKE perfection on earth?" Sure, Jesus has some decent ideas, although pretty much all of them are not unique to him and are common threads in the moral system of many religions or philosophies. But give him some credit. But don't blind your eye to the crap! Cursing a fig tree? Preaching in parables so many listeners will stay damned? Curing blindness with spit and mud? Telling his followers they have to hate their parents and relatives and love only him or they cannot be saved? This stuff isn't even consistent with the half-assed "morality" of the ten commandments (some of which are OK, or would be if the prescription for breaking them weren't to be stoned to death by the tribe, and others of which are sheer nonsense)!