I know this is just a joke.
But he did mention that they had the genetic capability that enabled them to "become hulk".
Could they both be mutants in the MCU?
Its starting to look like mutants in the MCU work in a very particular way, instead of being born with the x gene and getting your powers with puberty, you are also born with an x gene of sorts and its activated by some event.
Like Ms Marvel with the bracelet, Scarlet Witch with the mind stone... and maybe hulk and she-hulk with deadly gamma exposure?
I'm going to wait for more mutants to surface, but that could be a good way to explain mutants in the MCU... "oh they were always around, they just never got activated"