Obviously they're different technologies, however the main purpose of their implementation is for reduced fees. There'd be no reason to implement these technologies otherwise
Fascinating. I need to research this more and understand it more. Assuming it's true which seems likely, this needs to be much more widely dispersed information. Planck fee!
Maybe, in a unconstrained blockchain, like BCH is. Not in BTC. Miners in BCH could find that there is less risk of orphans with graphene, and could lower the min fees.