In the original Tsukihime, the recommended order for the far-side routes was Akiha -> Hisui -> Kohaku. However, while it was impossible to do the Kohaku route before the Hisui route, there was no such enforcement for ordering of the Akiha route relative to those two; it could be done (as recommended) before either, or after-Hisui-but-before-Kohaku, or after both.

In the remake, there's noticeably more route-order-enforcement already. In the near-side part of the remake, Ciel's route is gated behind Arcueid's, unlike in the original Tsukihime where those two could be done in either order relative to one another. (Albeit with Arcueid's route as the recommended starting point.) Thus it seems plausible that similar such stronger enforcement will be present in the far-side part of the remake as well.

If the remake were to strictly mirror the original's recommended route-order, we would expect Akiha before Hisui before Kohaku. (With Satsuki inserted at some undefined point in the sequence.) However, in the Tsukihime -The other side of red garden- trailer, the order of character-appearances is Hisui, then Kohaku, then Akiha, and then Satsuki. So many fans now theorize that that will be the far-side route-order in the remake, adjusted from the original.

If more than one route-order is possible in the remake's far side (in a manner that isn't e.g. a bug that gets patched out soon after release), the market will resolve to "Multiple possible route orders". Otherwise, it will resolve to whichever order is enforced.