For the first one, I'd check out fatebegins. She writes a LOT of a/b/o and only bottom!Jared, and usually the omegas are meant to be cherished.
http://archiveofourown.org/users/Fatebegins/pseuds/Fatebegins/works?fandom_id=12756

My personal favorites are these two
http://archiveofourown.org/works/987440/chapters/1947241
http://archiveofourown.org/works/577768/chapters/1036476

This one is Jared being harassed when he goes into heat at school but Jensen takes care of him and it's very hot/sweet.
http://archiveofourown.org/works/1153837

This one kind of fits one and three, with omega!Jared and mob boss!Jensen
http://archiveofourown.org/works/1121488

This is a really wonderful verse where both Dean and Cas are in love with Sam and they end up in a poly relationship. Not really destiel though since it's mostly focused on Sam.
http://archiveofourown.org/works/1570853