Yeah Scoots, while good for many, are ones that, due to little ability for adjustment/fastening, don't tend to work well for feet that aren't well shaped & maintained.
Hoof Boots Australia have many different types & info on the boots they sell, to get a good idea. Also Easycare Downunder have a large range, and there's a section with info on comparing different boots for different applications/hoof form. You can use this info to help you work out whether other brand boots will work, not just Easycare ones. But I think the ones you're talking about on the Hoofboots Aus. site that are really adjustable may be the new Easycare Furies. Look great, haven't tried them myself yet, so can't tell you first hand tho.
If you're looking at full day(or more) hikes, something like Trails, Cavello, Fusion etc probably won't work, as the 'high profile' ones, esp if not perfectly fit, have a tendency to rub, if on for long periods - they're more for your 'low mileage' rider. Also, depending which area of the BNT, much of it is rather... precipitous and gnarly country, so while you might be going slow, you'll want decent boots to hold up. I'd strongly consider Epics, as another good possibility - you can buy them to fit the flared feets now, do the wire/clasp up tightly, and there should also be room enough that while not ideal, when the flares have been dealt with, you can put thicker pads in the boots to keep them tighter, so they should still do for easier riding. Renegades are another which I think would work well, though I haven't actually used them on flared hooves, but I think they should tighten well enough. Just not sure how they'd go if much too big, as for when the flares are dealt with.