On that topic i think Romans, Carthaginians and most Greek civs could have Siege Tower too (current model as placeholders, maybe new ones later).  

Tried to have it fixed in the next release. Here is what Claude commented: "Isn't letting me pick a replacement". Most likely those templates are supplied by another mod installed on the tester's machine. Then they aren't missing: they show up as one "N templates … come from mod X" finding, and there was nothing to replace. Choose replacements…, and a double-click on that finding, now offer to replace them with the game's own templates, chosen one by one in the usual table. The other possible case is an actor (a model placed directly, actor|…): the message now names those and says to replace them in Atlas. It's still worth asking the tester which mods they have installed. Yes, indeed, switching from Findings to Convert means pushing the convert button (or selecting the tab or the menu). Finally, when everything is finished, there is the output button (I don't like that button labelmyself but was not able to come up with anything better yet. "Do it" doesn't look so fancy and repeating "Convert" might be confusing)

I suggest using 2 or 3 differently-colored "smoke" textures/particles to give the mushroom cloud some visual depth.   Also, for Mars, you could definitely start with the Nubia terrains.  

I don't the the tool likes these "|". So if the template is actor|flora/trees/pine_animated.xml, it says "manual edit in atlas" Also, the big button says "Output" in the convert tab. Is that intentional?

Now, that would be something quite different; I plan to use the grand strategy mod for a campaign map set on Mars.