Dammit. I just realized, thanks to a comment someone left on one of my fics, the real reason Odin didn’t murder Loki at the beginning of TDW.
It wasn’t because Frigga nagged him out of it.
It was so that when Thanos showed up, Odin could offer to hand Loki over to be tortured and killed in hopes of placating him.
I hate it when I figure out new things about these damn movies.
… which leads to the possibility that Odin knew Loki wasn’t dead and was being tortured but didn’t care. Could even spin that into Thor knew he wasn’t dead well before he showed up on Midgard, hence Thor’s lack of surprise about Loki’s survival and focus on just getting the glowy cube toy.
I really think Odin knew Loki wasn’t dead. For one thing, Thor arrives on Earth with intel about the Chitauri which Loki never got the chance to tell him. Where did he get it from? Probably Odin.