My myth pretty much only needs two spells. For mobs he only carries Frog, Colossal and blades. For Bosses I add in some feints/traps and Calendar. I really didn't use minions much past the early levels, however the lvl 75 minion does come in handy during certain boss fights. The one cheating boss in Khrysalis comes to mind, Tymen Whiteflame. She cheat casts mana burn every 3 rounds. If you are doing it solo, you are always her target. The minion provides some cover to allow you to setup some without always losing pips before being able to hit.
My myth is in Khrysalis and mostly uses two myth attack spells, Basilisk and Frog. I tend to use frog against fire mobs because it would be an extra step to convert meteor strike, fire dragon, and rain of fire (my myth has fire mastery). If you solo often with myth, I recommend buying fire mastery amulet even though it cost crowns (it super worth it). I did rely on minions up to dragonspyre before beginning to use them again in Azteca. My myth heals using power link in battles (really convenient in boss fights). I don't use calendar because I find Medusa's two round stun more useful and cost less pips. I substitute Basilisk for Medusa against myth bosses.