All node groups work with blender version 2.81. Technically getting these working with 2.80 should just be a matter of reverting back to the old mapping node (since this was altered in 2.81).

Yep! By purchasing you also get to help me out (which could be a plus or minus, depending on who you are).

Of course! I've decided to take a percentage from each sale and donate directly to the development fund (because they deserve it) :)