I'm glad that a discussion about different strategies has started.
I've read everything, and here's my suggestion for the first day of the game.
The optimal strategy for dealing with the Leprechauns is, of course, to attack them with one Sandro, casting Sadness, then switching to defense and enduring one hit from the Leprechauns. After that, naturally, poison them with a counterattack, and then run around the battlefield until they die. And after that, I would advise you to befriend the Fairies. To do this, I exchanged almost all my resources for gold and bought a second hero, a Mage, and gave him the Charm skill. After that, Sandro eliminates the Fairies in two turns, reducing their number to 33. Then, the Mage goes to them and befriends 5 Fairies. After that, the Fairies defeat all the Skeleton gatherings and the gathering of Squires and Peasants. The Mage activates the Sawmill and reaches the Golden Drake, escaping with it to the Fortress. Sandro's corpse is also taken to the Fortress, where everyone happily celebrates Christmas, sings songs, and goes to sleep.
I also tried using Diplomacy instead of Charm, but it doesn't seem to work. Does anyone know what its special ability is?
Good luck to everyone in the Tournament! I have a small time constraint today, so I will answer all questions later!