These really look great.
I decided to make a much more simple summoning aspect to the game without using cards. I was afraid making another school due to balancing. Looking through your cards I think you did a really good job balancing. Yours looks more like a official expansion. Mine is more like combining 2 games.
I thought I would share this as well
This expansion uses the City of Thieves gangs. Each wizard gets their own sheet and is allow to summon one character at a time. Once the character is summoned the player can activate either the wizard or the summoned character to move and/or attack. The summoned character does damage equal to the value rolled on their attack die. Ranged combat uses the same rules of LoS. You can discard again to summon another character breaking the previous one. If an enemy wizard or character enters the same space as another summoned character, that character can attack the entering wizard/character as if they had been activated( they can aslo move before or after attacking).
To summon a character the wizard must discard their entire hand.
1 card = roll d4
2 card = roll d4
3 card = roll d4
4 card = roll d4
5 card = roll d4 +/- 1
6 card = roll d4 +/- 2
7 card = Pick your character
Summoned characters dont have life but act more like a rose bush. 3 damage causes a crack and causes the spell to break.