Well, the storylines in 'Red She - Hulk: Planet Hulk' are quite engaging. It shows her in a whole new environment and the challenges she faces there. Also, her interactions with other Hulk - related characters in 'Hulk Family' story arcs are worth mentioning. They add depth to her character and the overall Hulk mythology.
The Red She - Hulk's origin story involves Betty Ross. Betty was exposed to gamma radiation which transformed her into Red She - Hulk. This transformation was part of a complex series of events in the Marvel Universe. It was also related to her relationship with Bruce Banner, the Hulk. Her new form gave her superhuman strength, durability, and other powers typical of gamma - irradiated beings.
Sure, She-Hulk is related to Hulk. Jennifer Walters, aka She-Hulk, got her powers because of a blood transfusion from her cousin Bruce Banner, who is Hulk. This connection is a key part of their storylines in the comics.
Captain America would be a great addition. His leadership and moral compass could guide Hulk and She - Hulk when they face difficult decisions. And his combat skills could come in handy during battles.
In many comic versions, She-Hulk gets her powers after being exposed to gamma radiation, similar to the Hulk. But the details and circumstances can differ in different story arcs. Sometimes it's due to a scientific experiment gone wrong, or a deliberate attempt to gain powers.
She-Hulk became She-Hulk because of a unique set of circumstances. Bruce Banner's blood, with its gamma radiation, entered her system during a medical emergency, and that's what caused her to turn into She-Hulk. This event changed her life forever.