I can't confirm that it's 100% impossible to still book your entire ticket with a 1-night stay, but if the other poster was correct, it appears this "loophole" is being addressed.
But, given their IT track record, it would not surprise me at all if some people can still do this even after they have ostensibly closed the loophole. After all, if ANYone can find a work-around, it's US!
Also, I saw your reply on the other thread and I think perhaps the answer I got was not to the question I asked. It would appear that you cannot book every day of your ticket at the 60-day mark from check-in (which is what I and probably others were thinking), but the 1-night stay may, in fact, still open up a "rolling 60" from the date you are reserving FPs for, so that would still provide a significant additional benefit over the "rolling 30" you get with an exclusively offsite stay.