I numbered your points for clarity.
1. The unarmed mechanic is pretty poor as there is no perk tree in Vanilla for Unarmed Combat and I think the damage is always the same, regardless of level, regardless of One-Handed, Two-Handed or Dual Wielding Skill, regardless of Health or Stamina and regardless of the hidden stats STR, AGI, END etc.
2. Unarmed Attacks are melee combat. They are hardly missile fire or spell casting, after all I think you meant "weapon combat"
3. You could, possibly, use Armour Rating if you had a script/hidden perk system as I mentioned above that related AR of the gloves to bonus unarmed damage. As you temper them up, the damage bonus would increase.
4. Smithing allows you to temper weapons:
a) which have intrinsic enchants due to the material of the weapon (such as silver against Undead and Lycanthropes, although Vanilla does not allow this and even mods that allow the crafting of silver weapons will not change the bonus damage vs undead when they are tempered);
b.) enchanted weapons which have spell-like properties, such as Fire and Lightning damage;
but Smithing only increases the base damage of the weapon, not the enchantment. The strength of the enchantment depends on your Enchanting Skill and the reagents you used at the time you placed the enchantment on the weapon.
The Strongest enchantments use the largest Soul Gems and the enchanting is done with all Perks and Enchanting Skill of 100 while wearing gear that enhances your Enchanting skill and also after drinking Alchemical potions that increase your enchanting skill, just as the most powerful weapons and armour are made while wearing gear and drinking potions that buff your Smithing Skill.
Tempering an enchanted item later on with massive Smithing Skill can improve an already tempered weapon, but will not change the strength of it's Enchantment.