I climbed Olympus one Feb in the late 1990's. We were pretty stoked to have a First Winter ascent, at least for a few days.
Someone in our party dug around and whoever he talked to speculated we were areound the 7th or 8th FWA.
Was a good trip. Slept in the shelter and then again on the top of the snow dome. Summit block was interesting. Walking up the Hoh was a little worse in winter thanks to the blow down, many downed trees to navigate. Avalanche issues were not a big problem thanks to elevation, goes without saying, low elevation and near the Pacific.