Can I use Ortho4XP generated sceneries with Four Seasons?

Standard Ortho4XP generated sceneries aren't compatible with Four Seasons, since they only include a set of texture, the one taken from the satellite.

But you could take a look at Winterizer as referenced in the documentation.

The downside note is that you won't get the granularity (read "number of seasons") that the standard textures set is able to produce.