1. It's unclear what it means that the number of passable cells is not the same.

It means that a unit under the effect of "acceleration" will move, for example, 4 cells, regardless of its "native" speed: 1 (slow); 2 (medium); 3 (fast)... I don't think I need to explain that in the first case, the effect will be +3, in the second +2, and in the third +1 ;)

If it's the third option, then it's already clear, so what's your disagreement?

I don't know what you meant by the third option, but I don't think that when (for VDV) the magic effect "acceleration" is written
"increases the squad's speed" - it's clear to everyone (including you);)

2. "reaches the enemy opposite him, and accordingly, the neighbors."
Again, the question: does this mean that the units are in their starting positions?
In that case, not always will it reach the neighbors, because the first, third, and fifth rows protrude to the left.

Yes, of course, it meant that the units are in their starting positions, and regarding the neighbors - read my quote to the end, and you will find your mistake yourself;)

Added after 7 minutes

Here's a save with 20 fairies and 4 gnomes!

If this save is to confirm my words, I welcome you, but I'm afraid you were inattentive to my comments again ;)
for reference, I'll say that in the VDV reference, it says that the maximum army for a sorcerer is 18 butterflies and 5 gnomes - which I, in turn, doubted and proposed my version of 20 butterflies and 4 gnomes...
P.S. So, are you for me or against me?