How is armor in skyrim classified

If you're going for a tank build (stand there, violently attacking and taking tons of damage) go heavy. This would be melee > magic.

If you're going for a kiting build (run around, fire off spells, then run in and attack) go light armour OR (IMHO a better option from what I've seen; the stat boosts are huge) enchanted robes of something. This would be for a magic > melee build.

And if you're looking for bonuses, I believe they are equal. If not, just enchant your own.

70 heavy armor (required for Conditioning) is a long way away. What you really want to solve the sneaking issue is the Muffled Movement perk at 30 sneak (50% noise from armor) and the Muffle spell from illusion.

The survival issue is simple - don't dual wield. Add a shield and you will live. Blocking is a huge damage reduction, but even when you don't block the shield adds armor!

Stamina isn't a big deal if you spend a handful of level ups on it and get the Restoration(40) perk - Respite (Healing spells also restore stamina).