Fel Armor and Demon Armor are the only two armor buffs Warlocks have so that should be simple to implement. I didn't know you were leveling up a warlock. This is very impressive without having a max level one to test with!
Soul Harvest resting should occur when the user does not have food/water, Soul Harvest is not on cooldown, and the user is not in combat. Not sure how difficult this would be to implement but I do this to save food.
I tend to cast Life Tap until my mana pool is full, and then cast Soul Harvest to regenerate the health I lost while casting Life Tap.
Fel Storm is an ability the Felguard has (Demonology spec only) and should be used when there is more than one mob attacking the user and the user is using a Felguard.