In the Marvel Comics universe, especially in the Spider-Man mythos, different characters can acquire similar powers through various means, such as being bitten by a radioactive spider. In the case of Miles Morales, he gains his powers in a different way than Peter Parker.
Miles Morales is bitten by a genetically altered spider created in the Ultimate Universe (Earth-1610) as part of a project by Oscorp. This spider had been engineered using DNA from Peter Parker's original spider, which is why Miles gains similar, but not identical, powers to those of Peter Parker.
If both characters were to be bitten by a spider at the same time, it would raise interesting narrative possibilities. One story could explore how their powers might interact or clash with each other, or it could introduce a multiversal concept where different versions of Spider-Man exist simultaneously.
Additionally, the simultaneous bite could create a thematic juxtaposition between the two characters, allowing for an exploration of their different backgrounds, motivations, and character arcs. The nature of their powers could also evolve differently due to their unique psychological and emotional states at the moment of the bite, leading to distinct interpretations of what being a Spider-Man means for each of them.
In summary, while both characters can acquire spider-like abilities from a spider bite, how that occurs, and the implications of being bitten simultaneously, would depend on the creative direction of the story being told.