Heroes 5.5 WarGame Edition - Tactical Edition.

Zealous rebels => Guerrilla rebels
I like it.

It was rejected as incompatible on the AG forum. I had to revert to the previous version - zealous rebels.

Accurate archers => Long-range archers
Long-range? The adjective is not used for people, but for artillery. I have never seen it used for people. I suggest "elite archers" - this was used in "Rome: Total War" to denote a similar unit: regular archers had a short range, while elite archers had a long range, and this was the main difference. Another option is "garrison archers" to show the value of such units in defending a city.

The first tier of archers is called "armor-piercing crossbowmen". I don't see any reason not to use similar adjectives for people using weapons with such properties. The fact that they haven't been used before doesn't mean that their use is illogical. Garrison and elite archers characterize archers much less than "long-range". Moreover, these are not elves, so they don't need to be elite.

Guard swordsmen => Guard swordsmen
Just guards. The type of weapon is never specified in such cases; just remember the "cardinal's guards," who were armed like musketeers. And yet, no one called them guard musketeers.

Anyone can be a guard, not just a swordsman. It is very important to maintain the associations with the real unit in the name. Guard swordsmen, for example, are named so because they are elite swordsmen, individually the strongest among their peers (no counter-unit). In contrast, armored legionaries have a strong defensive formation, which may be more useful in war than the strength of individual infantrymen.

Heavy armored men => Armored legionaries
Legionaries are, by definition, armored men, if I'm not mistaken. Even if not, maybe "heavy legionaries" would be better?

I moved away from the word "heavy" to get rid of the nonsense - because there are no "light" armored men.

Battle griffins => Storm griffins
Cat-dogs... Griffins are griffins. Storms are storms.

I couldn't find a better name for them. The English version is Tornado Griffins, but it cannot be translated into Russian that way.

Militant monks => Battle monks
It sounds paradoxical. First, battle monks, then berserk hamsters... There are special names for people who live in a monastery but are not monks, but are warriors (in Russia, for example, these are "black monks"; you could call them that. No, I understand that in Heroes, monks are traditionally a combat unit, and you, Nargott, are not to blame for this, but talking about "battle monks" is still too much, in my humble opinion.

Heroic monks are precisely battle monks. If a warrior in melee combat takes down several armored men, can he be just a simple priest?

Holy clerics => Field clerics
I don't understand how clerics are related to fields... Maybe "campaign clerics"?

In principle, yes, but I still don't like either option, although it's no longer "over the top," as in the case of holy.

Knights of Justice => Retinue knights
Retinue or knight-retinue would sound better, in my opinion.

Possibly. It's a matter of taste; we need several votes to make a decision.

Angels of Life => Angel Regents
Whose regents?

Regents of monasteries. Wikipedia

Assassin League => Assassin Poisoners
"Poisoner" already includes murder, that is, assassination; it's redundant.

An assassin is a professional killer, which a simple poisoner is not necessarily. But "poisoner" includes his specialization.

Dungeon gladiators => Interceptor gladiators
What do you mean?

"Dungeon" does not convey the essence of the unit, but "interceptor" does. This unit is valuable primarily as an interceptor of enemy attacks. In battle, it has the "taunt" ability.

Ghastly liches => Unholy liches
So, does that mean all other liches are pure as the driven snow? Well, somehow... They could be cursed liches.

I couldn't come up with a more suitable epithet. A lich is, in general, a one-time, heroic, and not a mass character. Therefore, their classification is not developed at all. The word "cursed" is unlikely to be better, especially since it is already used for the zombie alt.
Moreover, in Ashan, the undead are devout, but unholy liches are unlikely to be.

Blazing spawns => Sulfur spawns
Some not-so-euphonious Anglicism, these "spawns". It sounds like slang, and it is. It's better to come up with a replacement.

That's exactly it; the Russian translation of "spawn" never really caught on. Everyone confuses them with level 6. You can't call these little creatures demons, just as you wouldn't call a peasant an angel.

Impulsive? Well, that's like in some psychological questionnaire; you could add eccentric Vikings, introverted Vikings, or something like that. It's better to have something like "furious Vikings".

Furious Vikings are unlikely to say anything, because there are plenty of furious fighters, both in the literal and figurative sense (with the "fury" ability, which, by the way, they don't have). Impulsive, on the other hand, is very appropriate for the "bloodlust" ability (+8 to attack and +2 to initiative for 1 round when taking damage).

Defenders of Gorn => Fire-throwing jarls
Fire-throwing? You were probably trying to replace the word "fiery," which is used too often and therefore not very good to use. But "fire-throwing" refers to weapons, not to jarls; the word doesn't fit here. You could then have "jarls of fire" or something like that, but definitely not fire-throwing.

Again, I don't see any reason why a word that applies to weapons cannot be applied to warriors. Troops are, in essence, weapons for an army. And if these troops are famous for their long range, armor-piercing ability, or fire-throwing ability, then they deserve a corresponding nickname. After all, what does "fire-throwing" mean? Throwing fire. Does this apply to the unit? Yes. Are there other synonyms with the same meaning? No.

As for the term "fiery," in its pure form, it is used in WGE only once (Fiery Dragons). In all other cases, it was possible to avoid a direct repetition (Flame Veterans, Blazing Nightmares, Fire-breathing Hounds, Fire-throwing Jarls, Sulfur Spawns).