I should be in bed already, so I'll try and answer these questions and then go over character sheet(s) tomorrow.
@ERode I was flexible going into this, but I'd say based on the general consensus this will lean pretty anime. To answer your question more specifically:
An initiate is a passable combatant, far more skilled than your average civilian or simple town guard. It's not outside the realm of possibility for them to destroy a small house on their own, through strength or magic.
The Adept cover a broad range of skills, but they should be able to hold their own against mid-level creatures, and at the upper end their magic could wreck a city block.
The Avowed 3rd Class is where you start moving faster than the eye can follow, and leaving craters with every blow, and 1st Class Avowed are the equivalent of S-Tier heroes in One-Punch Man.
As for the top tiers of the world? The guild Captains could possibly level the city on their own. A world-class mage can bend the fabric of reality to teleport an entire castle, transport themselves to Dream in the flesh, or create new and twisted forms of life.
@Psyker Landshark Physical prowess is definitely still a viable path, and some of the strongest in the guild don't use magic.