I played the third one in the last version; this map seems to have changed the most of all three campaigns compared to its single-player version.
I decided to main Gotai, because in single-player it was definitely unrealistic to win with him without shouts, but here we start with everything except combat (pity) and rage (no pity). Overall, playing as Gotai has at least 2 serious pluses: you don't need to spend resources on one-time spells, and at high levels he doesn't care about mana drain from devils at all—all shouts cost 0.
The start was good; Kane managed to win and keep all the centaurs (a juicy demoralization procced on the seduced peasants) and crossbowmen. In the first week, Gotai made it to his dwellings, while Zehir cleaned the starting zone in parallel, and I tried something (not very successfully) with Railag. Closer to the third week, I moved Zehir to clear the respawn toward the sea, and Gotai went on a foray to take the dwellings. The build came out just perfect: full log and machine + shouts on charms and empathy; fighting on Gotai's free scarecrow is a pure pleasure. I took the same-type units as the last base; by the time Shadowear arrived, I had intercepted probably more than half of the dwellings. I didn't bother with the catapult quest—it's essentially unnecessary anyway—his army is really weak, like 3-4 times smaller than the one that comes in single-player with roughly the same number of dwellings and a completed quest. The only downside to this situation is that most enemies in such a state are much weaker than my main and not only refuse to attack the city but simply run away from battle constantly. Often you have to catch them on the territory behind the inner garrison, which naturally involves the risk of bumping into yellow heroes. In short, I killed Shadowear easily, but because of the field battle, it's at least some kind of challenge in terms of winning with minimum losses. There is a bug—when his opponent is an orc, the casting of the starting counterspell fails and the battle freezes; you have to use a script to unpause (it's unlikely they considered that there would be perverts who would play this as an orc :D).
[spoiler=
Kane's Starting Battle -> Shadowear]





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After the battle, I made a foray and cleared the yellow's central zone, took almost all external garrisons, and snatched Sandro's cloak from a hundred blood-eyed cyclops. The scarecrow with the little cloak worked very, very well in the fight against the necromancer, whom I again had to hunt down behind the garrisons. It could have been even easier; I was short on money to upgrade about fifty horses.
Nurzugur



Meanwhile, things were quite sad for Railag. There are few decent breakthroughs at the start; he quickly caught Darkness and I decided to build a combatant on Darkness, but the stacks in the dwarven underground quickly explained that this is clearly designed for killing with chaos invisibles. Plus, the game mocked the poor elf with zero attack stats over 15 levels. Various titans stood in the way of half the necessary items; overall, the guards are quite strange—for example, in the central part of the dwarven underground zone, the stacks are weaker than at the entrance to it. At least he fought off most of the outposts, even though his role is to hang as dead weight until the very end of the game. In short, Railag is played purely in semi-AFK mode and eats up part of the economy; however, when playing an orc, it's actually easier to build the economy, and by the 3rd week Isabelle was steadily pumping out horses.
Gotai, on the contrary, is all set; he's already collected almost everything possible from the map, and a couple of demons that followed were defeated without much chance. I shifted the car to attack; again, the fight had to be in the field (though with these guys it's more of a plus).
Ir-Ro(Kha)-Bar




Next—the first problematic stage. Ixclicta arrived—a solid army (especially compared to the others), dwarven set, which makes trades very difficult, and she casts Vengeance, which an orc obviously has nothing to counter (maybe banning Light would have been worth trying). Also a terrible week—morale/luck rolled poorly. Naturally, she doesn't want to fight in the castle; the field battle results in very serious losses and the loss of almost all horses in favor of saving shooters.
Railag's life improved somewhat with the drop of Berserker in the mages' bank; he broke through almost everything with two hundred furies, except for hordes of titans and such.
Ixclicta


Next—Pyrrhus; here, the unbought mage troops simply arrive, ZOO is leveled with Wind, phoenixes shoot back, and elementals are scared off by Sandro's cloak. An easy fight.
Pyrrhus


Now for the hardest stage of the map. Udun arrives; this is always a turning point in the mission where there is no guaranteed winning strategy, and on an orc it becomes even harder. A terrible special ability that breaks the starting ATB, a mandatory fight outside the castle (if you stall, Khan arrives and they merge armies, making victory absolutely unrealistic). However, I noticed one feature of the special—namely, that the spot where the unit is recreated depends on its slot in the hero's army interface. With this knowledge, I adjusted the build—moved the wonderful orc same-type units to def, Light ban to Darkness ban (this is complete trash, but there were no better options). I spent a long time rolling for a good starting ATB layout and managed to get a situation where both shooters didn't teleport straight into the crowd of enemies. I lost a lot of the army, but eventually managed to win (the worst part was actually losing 4k peasants who gave gold like a capitol). I noticed an interesting feature of the script that creates stacks in battle—apparently, in this situation, the game does not consider base stacks as lost, and those units that I didn't lose completely were restored to their original numbers after the battle (another plus for the argument that the special should be redone with a proper mechanic). But generally, any hero with magic would have killed this easily, so this difficulty is specific to my walkthrough path.
Udun



Against Udun, Khan became a total weakling—even worse in stats, he lost the wave. I bought a stack of chieftains and daughters; on day 5, I got +initiative from the Sanctuary. He finally decided to attack the city, where he was shot down by double-adjustments despite his dwarven set. Railag meanwhile got a vampiric item from the library and a staff from the Dragon Utopia. He brought out and upgraded almost all the meat except for trash hydras and minotaurs; Sigrif was killed easily, even though my build was very questionable.
[spoiler=
Khan, Sigrif and the end]





[/spoiler]
Objectively, the mission became much easier; I think any other hero should breeze through it. But I obviously prefer the single-player version—if I replay it, only that one.
Tried playing the fourth one as Ashu. Well, among the opponents, on one hand, there's again a bastard with Udun's special, and on the other—Zoltan's randomizer combined with a scream of terror; in short, I've put this aside for now)).