Nodding along with Echo. With few exceptions, I have never been able to predict which items will go back on sale. Of items on my wish list, I've noticed that jewelry and most Zella rarely go back on sale (or not until 6+ months later) but some of the T&B items do go back on sale by early September. The AGL shoes also often go back on sale, but I find that those are suspiciously "produced for the sale" because the details (eg. sole is usually synthetic, with no leather) are sometimes not the same quality as similar shoes in the regular line. My other "tip" is that I have found that if I can find the exact same item on the brand website, it will often not go on sale again within a month or two of NAS (in December, sure, but not September.) Interestingly, I have sometimes found the exact same item for less elsewhere (Patagonia and North Face coats and jackets) during NAS, and with those two brands I suspect that they get a lot of overstock or previous year's stock for NAS.
Would it be a possibility to buy now, and have shipped to family in the US? And then return if they don't work out, once you're back in the States?