I have a question:
Does the "Memory of Our Blood" skill (which grants 50-100 rage at the start of battle) work with the building in the town that grants 50 rage points? They don't seem to stack for me, and the creatures only receive rage from the town building, i.e., only 50. Or has this been fixed in one of the patches?

It works. Moreover, if you have 2 Orcish Castles, the bonus from the Castles will be 100 rage points, if 3, then 150, and so on.
I can tell you about the late game. I always play with the same strategy, and I think it's the best.
I play as Goshak. He's a good hero; he has a starting bonus, which makes clearing neutral creatures much easier. And his faction creatures are great. =)
Now, to the point:
1. Logistics - up to Path of War.
2. Attack - Tactics, Retribution.
3. Leadership - Aura of Swiftness, Battle Fury.
4. Education (I try to get it, but it depends on luck) - Fire Fury.
5. Here, if the game is very long, you can take a filler skill, Defense, Luck, whatever you prefer.
I don't take the racial skill "Strength Against Magic" because very few spells are learned, and the reduction is not significant. At least it saves a level.
You need to take and fully upgrade the first 3 skills. Education, if it appears, great. If Education doesn't appear, and all 3 main skills are maxed out, I would take Defense. In general, this is a debatable skill. I only take it in the very late game.