1.

I would suggest using the heroes found in prisons as you see fit! Because it would be a shame to break through the guards and find Ciel there. Why would someone who managed to defeat, for example, 100 Mighty Gorgons need a magic arrow with 60 damage?
Although, on the other hand, there are prisons without guards and with heroes of the first level. In this case, I would suggest dealing with them strictly, i.e., two levels and then retirement!

I propose allowing all banned heroes, except for Isra, Vidomina, and Mullich, if they are released from prison and have level 10 or higher, to be used. Because their guards are comparable to the guards of a Pandora box with all 4 spells.
2. I propose adding a clarification to the rules that it is not allowed to choose banned heroes as main heroes, because, for example, Mullich, Luna, and Ciel can do quite well in the beginning and up to level 3.
3. I propose correcting the contradiction, quoting the rules: If the aforementioned heroes reach level three or higher, they must be dismissed within the same day. ... I would like to point out that banned heroes can be used until they reach level 3, after which they must be dismissed on the same day.