HoMM VII Haven Units – Haven faction units from the seventh installment of Heroes of Might and Magic.

So, the information on the wiki is false, stating that it uses the Silent Storm engine.

I think you're confusing "engine" and "game source code."

Added 5 minutes later

if Heroes 5 doesn't have proper lighting on objects

I didn't know about its absence, well, okay...

I'm just visually assessing this, so the information isn't 100% accurate (but it's very close).
Perhaps there are some individual objects in the game (with special modifiers on the material) on which the light is calculated more complexly (what did you find out about the water surface?).
Again, somehow the models receive the effect of colored light from various crystals. In short, we don't understand how it all works very well.

P.S. But yes, a normal map would be cool.

Added 9 minutes later
I looked at the water in Heroes 5, and it seems that a normal map is indeed used there. We just need to understand how this specific object receives information about the light. I suspect that it is somehow related to the global lighting set on the map.