Heroes 5.5 WarGame Edition - Tactical Edition.

what if an Orc encounters a witch's hut on the world map with the "Education" skill? Will he get it? And how will this skill develop for him?

If it's not possible to completely remove it from the hut, that's okay – standard level 1 skills will be given instead: Diversion (with +1 to Magic), Intelligence, and Military Knowledge (with +1 to Knowledge). But there are no level 2 skills.

why?

I don't like this special ability. There's an exploit: you wait for Krag's first turn, and then you essentially have an enhanced Offensive Guard, because the hero is ahead by 25-50% on the turn order (and in the mod, even 35-50% due to the reduced starting turn order variance of 15%). And in addition to that, you also get an enhanced attack.

please explain in more detail – I understand that this is instead of Magic for the Orc, but what does Agrael have to do with it, and should it be renamed so as not to be confused with Luck, which is a skill?

Magic for the Orc works on a similar mechanic, but gives a bonus to 1 parameter, while Luck can give bonuses to different ones.
Essentially, the hero specializes in the "Luck" skill and is interested in developing it to the maximum.
The Luck skill:
+1/2/3 to Luck
+1 to a random, equally likely parameter for each level of the skill (updated every day)
Agrael's special ability turns this into +2 to a random, equally likely parameter for each level of the skill.

"Floating bonuses" from Luck or Barbarian Magic are not applied immediately at the beginning of the day, but immediately after the hero starts moving, so that the player can easily see the natural parameters before moving.

Why remove Education from the Orcs? Shamans exist!

Shamans here don't focus on Education, but on Powers (suppressions). They simply don't need it in terms of gameplay.
And why I removed it is because it's a poor skill for the Orc; there's nothing interesting about it, and all the good things have already been distributed among the racial or creature skills.
Fury of Fire is in the racial skill.
Mentorship is in the racial skill for Humans.
Endurance is in the creature skills (reworked into Barbarian Might: +1 to all parameters for each mastered Power).
Dark Revelation is not interesting enough to leave the Orc with a base for it.

Powers are not as weak as the regular suppressions in the original game, and can be used as key bases, since they have very significant combat bonuses. For example, a mastered Chaos Power gives +4 to Attack if the opponent does not have a mastered Chaos Magic (and neutrals don't), with which it mutually neutralizes. +4 to Attack is approximately +30% to damage to troops.