Rainjacket because you are going to be fishing in a temperate rain forest in an area that gets 120" or more/year and February is still the rainy season.
Any fly you have confidence in or that you like will work. Just carry some bright ones, dark ones, and neutral ones in #1/0 and 2. Me, I prefer to fish with Glasso Speys, G.P.'s, Ally's Shrimp in orange and purple, Ally's Cascade Shrimp, a few dee flies, and the occasional full-dressed, married wing classic Atlantic Salmon fly like Kelson's Kate and Purple Emperor.
But like I said, any fly you like or have confidence in will work, just remember to have some bright ones, dark ones, and neutral ones.
I wouldn't fish the OP rivers with a single-hand rod of less than 8wt for winter steelhead. And used to use a 9 wt single-hander to do so before I switched to 2-handed rods back in 1993. I had one friend who uses a 10 wt single-hander for winter fish on the OP.
A 14' 2-hander is all the length you really need for the OP rivers, and in some places on them a stout 12'6" or 13'er would be a better choice due to overhanging branches. I like to use a heavy line rod for winter fish because it makes casting large flies easier (this is why I use 10 and 11 wt 2-handers in winter), but a 9 wt will work just fine. If you are going to be fishing Skagit lines, a 7 or 8 wt would be good.