I got the same email you did, which is the first I've heard of it. But, trying to encourage Australians to head south in mid-winter is not easy!
I have to assume they'll use the front nine of Lost Farm together for the starting and finishing holes, and the back nine of Barnbougle for the middle section. (They'll have a nice halfway house that way.) I think they were working on a bridge between the two properties, that would cross over somewhere behind #15 tee at Barnbougle to behind #5 green at Lost Farm; if it's complete, they'll probably use that, rather than a boat.
When we built Barnbougle I had my eye on the green site for #4 at Lost Farm, as a tee for #17 at Barnbougle, if I could have got over there. It would have been a par-5 from there, more like 18 at Pebble Beach (mirror image).