144hr transit visit via Beijing/shanghai going to Chengdu

I am an Australian travelling first to korea, stopping for 4 days in Chengdu(china) for a wedding before returning to australia. My flight goes Sydney-Seoul-Busan(korea)-Beijing(2 hour transit)-chengdu(4 days for the wedding)-Beijing(2 hour transit)-sydney.

Am I eligible for the 144 hr visa free transit, since I have a layover in Beijing? Or do I need to clear customs in Beijing in order to utilise that visa? If so, is it possible to clear customs in Beijing in my 2 hour layover and then check back in to catch my connecting flight to chengdu, or is 2 hours not enough time to do this?

My boyfriend is Canadian and has ta same trip, except leaving from Canada instead of australia, and transiting through Guangzhou (instead of Beijing). Would he be able to utilise the 144hr visa free transit?