Welcome to the forum, Jonathan
I agree with Brian: Speyside in November is far from absurd, but I'd emphasise the short daylight hours issue, to the extent that if you are planning to use B&Bs I would request early breakfast when booking. On any long sections (e.g. Grantown to Aviemore) it's important to get going at first light so you aren't caught short by the early dusk (and carry a torch just in case).
Not sure that Brian is right to dismiss another extreme winter, though: the early arrival of the Bewick swans and pink-footed geese suggests otherwise! But I don't think the time of year affects the direction issue: some like to follow the Spey valley downstream with prevailing wind at their back to finish at Buckie, others argue for building up from short, flattish coastal days to harder ones ending at Aviemore. Transport logistics will pre-empt the decision for others.
I've just spotted an order for our
guidebook from you: that's great, it means you'll have the route updates including the new start in Buckie. Check this
post for a checklist of what has changed recently.