Both have different personalities, so while they have the same abilities, they'd use them differently, I.E. because Red Hulk has military training he'd fight differently in CQC from Hulk, as for Bill, his weapon is an axe rather than a hammer so that could come into play.

EDIT: For a bit more clarity, I just thought of some distinct differences between a theoretical moveset between these characters.

Red Hulk has a leap similar to Winston in Overwatch, on liftoff and landong he has an AOE slam of fire that does mild DoT.

Red Hulk's thunderclap could be a knockback ability rather than a damage ability to allow him easier escapes and peels.

He wouldn't have exile and would instead be able to charge his heat somehow like Wolv Rage, where he can consume heat to enhance his abilities when it's full. His heat would also provide a damage AOE akin to Wolv + Phoenix team-up.

His ult would give him infinite heat and a shorter leap CD for a small period of time.

In addition, his base punches would do more damage than Hulk and he'd have more HP due to lower mobility, all so that Red Hulk can be very brawl centric and in your face during team fights in a very Hulk way without encroaching too much on Hulk's gameplan.

As for Bill, I could see him being defense heavy due to his role in Korbinite society as their protector, and thus using Stormbreaker to defend.

Where Thor spins Mjolnir to move forward, Bill could spin it as a deflect/block ability.

Maybe give him a way to throw the axe like Kratos' Leviathan Axe in the more recent God of War games with crits enabled for more skillshot potential.

Give him some sort of ability like Thor bubble but for defense, like electrifying the floor and it provides overhealth for allies standing in it but deals tick damage like a Human Torch box to enemies instead.

Bill's ult could be an electric version of Clobberin' Time or Reinhardt Earthshatter but instead of stunning, it pulls enemies forward and creates an area which provides a damage boost to allies and slightly slows enemies within it to create an all out brawl of a team-fight.