If you are in rain AND wind AND if there are no trees (I recall Iceland being so far north is more apline so few trees, then you are going to have horizontal rain. I'm not sure the Fly Creek is good in these conditions. It would be nice to have two doors so if horizontal rain is coming in on one side, you can use the other door.

I have a Tarptent Moment. I do not worry about its strength, but it does have pretty severe condensation problems. It actually is well designed for wind.

I have a 2-man 4-season Mountain Hardware tent, but it is nearly 6 pounds. It is definitely bombproof in really bad conditions and has two doors.

Why don't you just wait and buy a tent when you get to Iceland? That way, you at least know what the locals use.