Fate. He was defeated from Pops' hug and died from burning in the sun, along with Pops, thus, he is now in the afterlife.
Maellard. Mr. Maellard is Pops' father and the owner of the Park.
With or without the gauntlet, Thanos is far and away more powerful than Thor. Thanos was considered by many to be one of, if not the most, powerful beings in the entire universe. He is physically stronger, more skilled, more intelligent and more resourceful than Thor.
Yes absolutely. Black Bolts whisper can level mountains and a full out shout can shatter continents and perhaps planets. However Hulk at his best has survived a lot worse then the most devestating shout Black Bolt could unleash.