The satirical force of Ecclesiastes and Job is implicit. We're not talking about standup comedy or laugh-out-loud jokes here.

God is implicitly mocked in Job because of the irony and bathos of setting the readers up with information that Job lacks. While God goes on and on scaring Job into submission, as though the reason for his suffering were cosmic and way beyond his comprehension as a puny human, we the readers know Job suffered because of a petty bet between God and Satan that stemmed from God's boasting about Job's piety. As Jack Miles points out, God is silent in the Tanakh after Job, so Job effectively reduces God to silence.

By mocking human affairs in Ecclesiastes, the author is indirectly mocking God since God would have created us. If life is meaningless and not so obviously part of a good creation (as in Genesis 1), what does that say about the intentions or competence of our maker? Ecclesiastes is very clearly part of a subversive, jaded, philosophical tradition which Jews would have appreciated best as the disappointments in their history mounted.

Assuming God doesn't wear clothes, showing someone his back would include showing his buttocks, but of course that's nonsensical since God wouldn't have a human body. Nevertheless, the text distinguishes between God's face and rear, and the point is that Moses is fit to see only his less glorious, rump parts. His entire back would be equivalent to human buttocks in that sense, in being less presentable or important than the human face (by way of analogy).

You're right about Moses and the promised land.

As for parallels between religions, I'm enjoying "The Shape of Ancient Thought," which goes through the many parallels between ancient Greek philosophy and Hinduism and Buddhism. Also Uzdavinys' "Philosophy and Theurgy in Late Antiquity" goes through fascinating links between Egyptian religion and Greek philosophy. As for Judaism and Hinduism, I think closer influences would be Egyptian religion and Zoroastrianism.