Bruno. AJ is more of a clubbing hitter .obviously a powerful guy but doesn't have the one punch power that Bruno and other others have . Whether AJ is a better fighter isn't the question .Frank has the edge in power
Until Wilder retires Bruno is the HW champion who retired with the highest KO rate. I will go with Bruno.
Hard to say. Both guys hit very hard but both fought a lot of weak opponents. Also the guys Joshua fought were bigger on average and he was forced to learn how to fight more cautiously after being stopped by Andy Ruiz. I’m uncertain