Well for those spells, I would use the INT stat for magical sort of spells, STR for physical ones, AGI for DPS/DoT/CC.
Before in one of my failed project I used these stats:
1. STR -> Physical Power, which covers Health, Health Regen, Attack Damage, Armor
2. AGI -> Speed, which covers Movement Speed, Attack Speed, Vision, Crit. Chance, Dodge Rate and CC Effectiveness (Stuns, Slows, Silences, etc.)
3. INT -> Magical Power, which covers Spellpower (stat used when casting non-physical based spells), Mana, Mana Regeneration and Magical Armor.