Another thing to think about is not really color balance, but rather fairness balance
Each Draft Booster contains 15 Magic cards and 1 token or ad card, with 1 Rare or Mythic Rare, 3 Uncommons, 10 Common cards, and 1 Land card
If Pyromancy 101 is countered or otherwise fails to resolve (probably because the target became illegal), none of its effects will happen, including teach
There are 4 rare (1%) and 2 mythic rare (less than 1%) scene cards that can be found in this slot
Gerrard's Wisdom is one and Heroes' Reunion is the other
If youre willing to wait until your fifth turn to have found the needed legendary creatures and are happy with a 75% chance of having Kolvori be a 6/6, then you only need a mere thirteen non-Kolvori legendary creatures, which is a much easier number to come to and still sounds acceptable to me