Quests and puzzles!

1. How to break through a stack of neutral creatures – physical elementals on day 1 of the game?
The conditions are as follows:
There is a sufficient amount of money for several heroes. :).
There are 6 physical elementals and 1 magical elemental in 7 stacks.
On the way to them, there is a +1000 experience point, so let's assume that the hero levels up as needed. :). Let's assume that you can hire any standard hero from the tavern, and even several.
The game version is SoD 3.2.

Your task is to break through the barrier! I'm waiting for answers.
The army consists of 2 units of level 1. :) Your choice.

My option is as follows.
Start with a merge. Day 1, upgrade a fairy.
1st attack: Ciel with one upgraded fairy attacks the army of psychics.
After visiting a +1 level-up spot where she gets +1 spell, her ranged attack is 75, which is enough for one unupgraded unit.
We attack, trying to kill all the simple units, using a ballista for distraction, which we took from the garrison :) (if it's a loss, we attack again with Ciel and the fairy, finishing off the simple magic users).

2nd attack
Garrison with advanced artillery and a ballista. The army is 1 upgraded fairy against an upgraded magic user. We wait and move behind them while they fight one on one. Garrison easily defeats him.