I'm far from an SH expert but can meekly attempt to clarify the "Yuan" vs "Renminbi" debate.

Renminbi is the currency's official name. It literally means the "People's Money/Currency" like we might say "Canadian Dollars, US Dollars etc"

Yuan is like saying "Dollars" or "currency" or "unit of money" is my understanding of it and is used most commonly. For example US Dollars in China are called "美元" Mei Yuan or American Yuan. Of course it does not help that they also often throw in the "gold (jin)" character “金” when talking about money/currencies.

Hope this has not made you more confused. In other words, use Yuan more often, and if you get puzzled looks, which you won't (for getting the tone wrong) you can always say Renminbi.