1. Do you think think there's a connection between Crystal Tower (Crystal-Like-Law), Jygallag, and Anuiel/Aedra?
No, why would there be. We don't know anything about Crystal Tower apart from its name and that its in Summerset, and just because Jygallag had crystals doesn't mean he's related.
2. Was it just me, or did anyone find the oppression atmosphere of chapel and Nine Divines religion, and indeed the "culture" of Imperials themselves, to be a less extreme version of Jygallag's Order? I mean, compare the stuffy attitude as shown by Imperials in Oblivion to Jygallag's Greymarch, and then contrast those with the culturally rich Nords, Dunmer, and madmen of the Shivering Isles.
No, what oppression atmosphere? The Nine Divines religion was hollow as far as I could tell, it wasn't fleshed out enough to be oppressive. That the devs didn't put any depth into the Imperial culture doesn't mean that they're meant to be similar to Jygallag. How does a "stuffy attitude" even remotely compare to the Greymarch?