Oil is traded internationally in dollars anyway. If they bought from the middle east they’d still be paying dollars.
It could be part of a back room deal to limit their purchases of Russian oil though.
No, they will not be paying in dollars. Only pay the dollar-equivalent price, but in other currencies. Saudi Arabia is accepting RMB from China for example.
Yes, but the price is set in dollars and then exchanged to RMB at the rate set on the floating market.
That won't always be the case. Basically, it's all about with whom you trade most. If Saudi Arabia finds themselves in a position where they have 50+% of their imports and export originates in China it will make sense to switch to RMBs to all trades, and the dollar price of oil, or other goods becomes irrelevant. And the Chinese economy is on track to become bigger that American by 2030.
Not anymore. China, Russia and india are exchanging in their own currencies.