It has some hills, but nothing of the rolling nature of 68. Haven’t done much time in Pittsburgh so maybe 230 on a Friday is when things pickup?

The turnpike, if it's open, should be fine. Of all the roads mentioned, it's IMO the most heavily plowed/salted, and if it's undriveably bad, it closes. The only bits on the turnpike that stick out to me as potentially spicey might be the climb out of Bedford to the Allegheny Mountain tunnel, and the series of S-bends descending from the Laurel Highlands west of Donegal. I wouldn't be worried about traffic around Pittsburgh, as 76 isn't really a commuter route, and you link up with 79 far enough north that you're not really in-range of traffic. 79 is then mostly boring and at worst rolling/sweeping, as opposed to mountainous and twisty. 90 from Erie to Buffalo I'm less familiar with, but so long as it's not actively lake-effecting (keep an eye on forecasts and radar), it should be fine?

Basically, of your options, to me that seems the most straightforward and least likely to cause problems, as all the roads on that route are major arteries that are well traveled and plowed, higher-speed limit (= more gradual turns and hills), and unless I'm mistaken, they're all divided highways, so if it you do get caught in a snowstorm, "oncoming traffic," at least, is one less concern to worry about.