You are correct  on both points. The armor functions like a second health bar that takes any 5 rolled against you, but 6s still hit your hp. The armor you wear affects your ability to evade. If you take an evade action on your turn, you get to roll to evade if the enemy lands a hit against you the following turn. Heavy armor can’t evade unless it has the shield. Unarmored gets to evade on 4-6, but doesn’t get any armor bonus.