A good alternative color for the Irish National might be yellow hose. I think that would look rather nice, actually, with bottle green flashes.

For the Isle of Skye, there are a lot of options. There are actually three shades of green in that tartan, and I find that all three colors of green Lewis hose we sell (lovat, loden, and bottle) work with one of the shades in the Isle of Skye. Purple is always an option. Brown hose and grey hose look quite nice with it, too.