All Guardians use the same abilities because all light comes from a shared emanation. For example, Crow was never taught Golden Gun and can use it because it's already IN him as a hunter. It's why Hive Wizards use storm trance, knights have sentinel, shields, and acolytes use blade Barrage and were never taught those abilities. These ideas are instilled at the moment of resurrection. It's instinct. However, there are slight variations between Guardians and Hive and you could certainly have some minor behavior differences like a Dawnblade summoning a larger Greatsword for melee sword rush attacks or dual wield Golden Guns, kinda like how Burning Maul came after Hammer of Sol. It remains to be seen if there's an actual limit and if Guardians actively try to develop new techniques because Arc Staff did kind just come outta nowhere and they retconned it to have always existed.