Definitely not. Spiderman has always been a part of the Marvel Comics universe. Marvel has its own distinct set of characters and storylines, and Spiderman is one of the most famous among them.
Definitely. Joker has been a staple in DC Comics for a long time. He's known for his chaotic and unpredictable nature, causing mayhem in the DC universe.
Brightburn isn't part of DC Comics. It has its own unique origin and story outside of the DC universe. DC Comics has its specific set of characters and storylines, and Brightburn doesn't fit into that framework.