1. By that time, temps will obviously be lower, and the ram's coats will be thicker...if doing a full-body mount the "feathering" on the legs is really cool and the coats are impressive, as contrasted with the summer coats of rams taken in NWT in July/early August or Yukon early August. Herb Klein, the legendary Texas wildcatter who was one of the sheep-hunting pioneers (see "Great Rams" I-IV by Robert K. Anderson), killed several rams early in his hunting years and early in the season, then later on decided that he liked the "winter coat" so much that he purchased full-body winter capes and had his taxidermist re-do multiple trophies...of course he had the money...but if it looked better to Herb...
2. Daylight will be shorter with fewer hours to hunt...but rams may be at lower elevations to avoid deeper snow at higher elevations. In 2016 I was in the Yukon and had shot a bull moose and a serious storm was coming in the next 2-3 days from the SW, and the ram I shot right before the storm hit was on the north "nose" of a bench off the mountain, with 10 other rams, feeding on the lower 1/4 of the mountainside only about 400 yards above the braids of the Whitestone River valley floor.
3. Be prepped with the best rain gear, know your layering, and stay warm so your not shivering when the time comes. It never got above 26 deg F on us in 2016 and we were there 8/31/-9/9.
4. The Lancaster family is top notch. "No question is a stupid question when you are spending the money". Ask whatever you think is pertinent, and they'll answer to the best of their ability. Talk with references and ask them about any negatives, perceived or real.
Best,
DWD