Additionally - when a refund appears on my credit card transactions, how do you categorize that transaction? Is there a way to link it to the original transaction that it should be "reversed" against?

Just categorize it as the same category that the original transaction was made in, and it will add that money back into that category

Oh... ok. So I was doing it as 'ready to assign' - as in, these funds are now freed up. Ok I hear, thank you.

Yes second this. It has to go back into the same category.