stupid refugium questions and setup

[Hightower]

Ok, I have finally setup a refugium, with the goal of nutrient export and pods.
It is above the main tank as a display gravity fed, with the pump pumping up from the sump.

forgive my ignorance, but why is everyone avoiding macro algae that would be asexual. dont you want it to produce so even more is exported?

If thats the case, what are the recommended macro algaes, (or avoid for that matter) and do I need to put live rock in it. Right now I have mineral mud and some live sand in a 10 gal giving it about 2".

Does lighting need to be on a reverse cycle with the tank or 24/7

Also what else to put in? Snails? other critters?

Thanks