I'm no expert on the day/early evening side if things, but I've been night time sea trout fishing for a good while.
Your rod size and line weight is around the norm for sea trout fishing. While the 5lb strength leader may be ok for day time and early evening fishing, I would certainly recommend heavier for night time fish. They have a knack of hitting the fly really hard sometimes, and remember the fish could be into double figures. I would recommend min 8lb, I use 10lb. The fish aren't leader shy at night, so you're better safe than sorry. I would also include a sink-tip in your line selection. Don't want the flies skating unless you're purposely fishing a surface lure. No need for a whole host of poly leaders if you ask me, keep it simple, a couple of lines and a choice of a few flies.
For flies, again speaking from personal experience I tend to only use 4 or 5 patterns. I see little point chopping and changing flies through the night, use the one which instills confidence, don't let the "am I on the right fly" scenario creep into your head. Bloody butchers are excellent sea trout flies, especially tied on some Salar hooks with a couple of JC cheeks. That is my fly of choice for the dropper. For the point I generally use a tube, water speed and depth will dictate it's construction i.e. Alu, Plastic etc. Again keep the pattern simple, a black hair wing, red throat, silver or gold body and some JC cheeks and you're good to go. Get the fly in front of the fish, at the right depth and generally it'll either take the first thing it sees, or won't look at whatever you put in front of it. So, to make things easy, stick to the 'usual suspects'.
*edit* Just read "you won't be fishing at night" Doh.