Eh....I dunno about all that.
It kinda don't make sense considering Loki could've strolled into Asgard at any time. Why come up with an elaborate plot to start a war, get your ass whupped by Hulk, just to end up where you could've went your damn self, with no hassle? Thor was practically begging him to come home during the movie, before, during, and after the war.
A more likely scenario is Thanos sent Loki and the Chitauri at Earth as a kind of jab, knowing damn well they'd most likely lose. Which is why he looked so happy at the end when the main alien said attacking Earth was a losing proposition....winning was never on his mind. He just wanted to test The Avengers.
Fred.