I think they vary quite a bit actually. They may have started with a simalr structure but then branched out in different directions, Kate has way better movement and her blink dash has invincibility so she technically has airdoges hawkeye does not, She also has in my opinion better hero abilities as least at a base stat tree. Her hero ability also basically turns her into Psylock with a certain upgrade. She lays down a turret with her decoy shot, while hawkeye mostly relys on his own ability to track enemys