Traveling from Australia to US via Hong Kong and Beijing

Hi! We're a family of four traveling from Australia to the United States, with a 5 hour layover in Hong Kong, and a 15 hour layover in Beijing. The plan was to get a hotel room during the layover in Beijing, as it's an overnight layover (we get in at 12:10 AM and leave at 2:40 PM). Do we need a visa, or can we apply for the 24 hour transit, then a free temporary stay permit? We have to collect our baggage between flights, as they are different airlines and we can't check it straight through to the United States. Three of us are US citizens and the other is an Australian citizen.

Thanks!