Does Delta have a Skymiles partner in Australia I can use to get back from Cairns to the US via Sydney or would I need to buy a separate Cairns Sydney Ticket?

Also lowest Delta One Skymiles awards I am seeing from SAN-SYD are 110,000 miles. Is that the lowest it goes? Also showing only 1 seat available. Do they open up a second one after the first is taken or are 2 available right at the 330 day mark?

Thank You