The likelihood of two non-identical buildings having the same height, even if they have the same number of floors, is very low.
The likelyhood of two independent buildings having the same height is very low. But for two rowhouses next to each other, I'd think it's not uncommon. Maybe I'm biased because I lived in one:Google Maps shows you where I lived
Though I don't know exactly how they come to be. Might be they were exactly identical when buildt, but were renovated at different times in different ways.
Either way, for the game, it feels like having them at the same height if they have the same floor number seems to make the most sense, even if that's not how it works in reality.
If the black building in the center was built before and adjacent buildings, then it would have made sense following the neighboring building.
Sorry, I can't follow. If it was buildt before any adjacent buildings, there wouldn't have been any neighboring buildings to follow?
The building order does not really matter. At least in p192c, we don't have any level 1 rowhouses, so the first building buildt on any tile would never be a rowhouse. Rowhouses and their rotation only become a thing with renovations, when the buildings are upgrading.
But on the building surrounded by roads on three sides, the situation is only clear if there are already rotateable buildings. If not, having the orientation towards the most roads is a good idea.
In p192c, rowhouses use the rowhouse cluster. Therefore, even if there is not a rowhouse on the adjecent tile, it is very, very likely to spawn in later. Since at that point in time the building won't update anymore (and it shouldn't!) it should be buildt appropriatly in the first place.
I don't think rotational buildings other than rowhouses are a huge concern here, either. They usually are only rotated so the front door faces the road, maybe with a little pathwalk connecting the door to the sidewalk of the road. Therefore, they should work fine as long as they face any road - which they still would.
In fact, I'd say it's more likely that a non-rowhouse would still face the same way as it's neighbour, since that means they are in the same street.
Now this goes too far for Simutrans, but quite often you would have a 'road for travelling' with no or few houses buildt at it, but instead, a lot of additional, smaller roads just to connect a bunch of houses to the 'road for travelling'. This means that there are less intersections on the 'road for travelling' (counting any garage or parking spot for a single house as an intersection) and therefore, easier travel. Since Simutrans is not Simutrancity, that concept does not matter at all - but it goes to show that turning the house 90° so it faces the same road as it's neighbour makes a bit more sense than facing the 'middle' road for no reason at all