I think it's safe to assume that kekkei genkai is to get the same treatment as mangekyo and origin of 9 tails; meaning that how a character defined it before was from ignorance and the rules and limitations had plenty of exception.. to the point that there were no longer fixed rules but instead q basic principle to which to adhere. Molding chakra of two elemental natures and combining them into use for the same jutsu. Don't most jonin have 2 elemental affinities?

The real bloodline limits are abilities granted by special conditions of the body or hereditary circumstances like byakugan, juugo's natural energy absorption.

Things like laser circus are theoretically available to any shinobi from any family or village as long as that shinobi can use the 2 elements.