I want a Dunmer that uses combat mostly and backs it up with archery. He'll wear either a mix of heavy/light armour or some special niche armour that sits in the middle. He'll use magic rarely if he's in a pinch.

But what I'm stuck on is what kind of armour would a Light/heavy armour Dunmer wear? I want it to suit his role-play (leaves Morrowind because of Red Mountain, hates Empire for leaving Morrowind during the oblivion Crisis, wants to join Stormcloaks, racism of locals puts him off and he joins Legion to protect and liberate his clan-siblings in Windhelm)

So what kind of weapons/ armour should a hybrid, to-the-bone Dunmer use?

Chitin.

Is that with Dawnguard? Currently only have Dawnguard.

Ah. Well its with Dragonborn.

You could wear a heavy imperial cuirass and light boots/gloves and some light shield. I don't like the imperial shields. If you can get one a Stormcloak officer helm looks cool with imperial cuirass. The helm would be a trophy from a defeated enemy. If you are not on pc you can get one for sure at the battle of whiterun if you can loot an officer/general before they disappear.

I would go with Elven gilded armor and elven weapons. Why not?