Exactly. On this map, with some luck (or the ability to reload), you can capture all the mines except for the gem mine (which can be taken on the way to the center) and the key master, although in a real game, without Lethos, Cyclops are a bit of a risk, but in this particular generation, the terrain helps. However, I play this map with 4 heroes on week 1, although maybe 3 would be enough.
We're waiting for the results of Waishan and especially Rathnik.

Almost, but...

1. You can take the gem mine with a support hero and one Fury, if you're lucky with the neutrals. That's how I took the mercury mine with Irbeth (it was guarded by upgraded swordsmen).

2. But the point is that, for the sake of a clean experiment, there was neither Lethos nor Waishan, and the second hero in the tavern wasn't a Necromancer.

3. Yes, the terrain matters (I placed 1 skeleton, 1+1 stalker, and 14 Furies) and lost 1 skeleton and 2 stalkers. But it's also possible with different terrain. Although you're right - it's dangerous.

4. Having a 4th support hero on the main hero can either lead to economic losses or a loss of the main hero's development tempo (treasure chests for money). Or am I wrong?

P.S. I don't know about you, but I find our communication pleasant and useful. I periodically learn something new for myself.