Having a Mage Pawn for Holy Weapons as your default enchant is a good idea. Heal, physical Status Restore, Flame Wall, Magical Status Restore are all great additions. 6th spell is a bit of a wild card imo.
As for Sorcerer, if s/he doesn't have Fulmination I will not hire him / her. Miasma is a bonus spell, since it's a fast cast and fights can get pretty hectic, especially if extra enemies get summoned to ths fight.
If you're Mystic Knight, go with Thunder Enchant to override Holy for specific monsters - Garms, Elder Ogres, Gorecyclopes, Death, and Living Armor. Eliminators are weak to Ice and Thunder both, but magic in general obliterates them.
Abyssal Anguish is another must if you attack physically at all and should kept up at all costs.
3rd Shield Spell is your wildcard. Holy Furor is an option, but the slowest spell in the game to charge fully. You can go with one of the Riposte spells, again, either Holy or Thunder, or a 2nd Enchant (Ice), for more flexibility against Banshees and Firedrakes, who are, in my opinion one of the most frustrating enemies in the game.
For sword skills, Full Moon Slash is a must because of its gratuituous iframes. From there you can mix and match as you like, but Great Cannon is considered one of the best skills in the game, for good reason. Blitz Strike is a good 3rd for mobility. Ruinous Sigil combined with Great Cannon can be absolutely devastating against enemies like Condemned Gorecyclopes and Living Armor, but require good positioning.
I'm rather partial to Stone Forest because when combined with Impact its ability to Topple enemies is second to none and it gives you a source of Fire Damage for Dragon Zombies, though it is a bit of a long charge.
Mystic Knight, particularly Great Cannon, is a bit weird. It's 2/3 Magical, 1/3 Physical. The twist is, your base strength has no bearing on the physical portion, it is based entirely on the strength of your weapon.
Abyssal Anguish is Dark Elemental damage that is based entirely on your Magick + Shield Magick. But since you're going to be attacking with it, Physical Attack is still very important.
If you're going to spam Great Cannon, level entirely as a Sorcerer. If you wanna mix melee and magic, balanced leveling is your best bet. The MK has good, balanced stats but tends to favor defense. After Level 100, Ranger or Strider are probably your best bet for balanced offense.