China Tourist Visa - Beijing 144 Hours Free transit and Do I need a Transit G in Guangzhou

I hold an Australian passport and plan to visit Europe and China as a tourist in August 2018 flying China Southern all the way.

I plan to visit Eurpore first and on my round trip home I plan to stop over in Beijing. The return plan is to fly from Frankfurt to visit Beijing. Can I apply for the 144 hours free in Beijing? After visiting Beijing I will be flying China Southern back home to Melbourne. From Beijing, the China Southern Airline plane will transit Guangzhou where I need to change over to another plane (about 3 hours at the airport ) to fly back to Melbourne. Do I need a free transit G in Guangzhou for the 3 hours at the airport? Thank you in anticipation of your advice.

Regards

Alice