Huge muscles wins a decision, Tony has proven a very sturdy chin against everyone, and great resolve when hurt. I've seen nothing from Joshua that says anything other than decision win, but Tony could play spoiler....again
Even though Thompson beat Solis he looked dreadful. Much slower and lethargic than the one that beat Price. Thompson is just another gate keeper these days, able to beat pretenders like Solis and Price but genuine contenders like Takam and Pulev beat him. I think AJ has the goods to at least be a decent contender so I's pick him to stop Thompson inside 5 rounds.
Thompson aged a lot over the last year or so, I don't think he has anymore big wins up his sleeve. Not against legit talents, he might be able to solve Wilder but that's about it at this point. Joshua, Parker, Jennings, all beat him now. Thompson had a nice career though.
Joshua is already too good and Thompson is just too old and doesn't have enough left to pull off that big of an upset. There would have to be something seriously wrong with Joshua, like a Price level glass jaw.
Depends when the fight takes place. Right now AJ would win but it would still be a huge, frustrating test for Joshua.