Pandora!

You don't understand. First, a zone of a certain size is drawn, then the race type is applied to this zone (for example, Inferno), then the landscape (possibly not lava), and then a Castle is placed (not necessarily an Inferno Castle; there may not be a Castle at all). It's logical that the starting spawn point coincides with the Castle for which you start.

Where did you get the information about the map generation sequence?
Until I get reliable information, I won't take it seriously (just kidding). ))
But still, I spent several hours sitting and trying out several templates and a bunch of spawn points, and everywhere I get the same result.
In general, I can only say that if a player starts playing, say, for Inferno, then in the Pandoras located in that location, they will give units from Inferno, regardless of the terrain (even if snow is generated). The main thing is what the main Castle is, because it seems that the computer generates the map in such a way that it is beneficial to that player. So, what's the point of, say, Tazar, who started in a Fortress, having 40 zombies, if it would be much better to have 40 Lizard Archers! In general, these are my observations. I can only say one thing: my observations are correct, because I spent the whole day today generating maps and checking, and I haven't been wrong once.
P.S. If a Pandora is taken, say, in a treasure where there are no Castles at all, then neutral units will be given (mummies, snipers, anyeaters, boars, etc.).