Thanks for your great feedback!
I appreciate it! 
Basically, I’m focused on my DoN MOD, so this MOD kind of just happened because I want to make a city like Minas Tirith (…some time in the future ^^)
I will try to stay true to the LoTR lore.
Btw, really awesome images (Kunming and Shilin) 
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Yes, -I have a limited time to devote to modding, there of the slow progress.
The intent is so give the biome more dense clusters of trees, that wont cover too much of the plains.
All desert plants will be changed to the temperate vegetation.
Since I feel that my Númenór MOD needs the white tree, I will eventually look over that option.
-So far, I have no intent of changing the mining loot.
Part from attempting to add Mithril Silver to my main mod that is 
The lighter the color, the higher altitude that mountain area carries.
This question is something that I guess you have to turn to an official modder.
I can’t give you an answer on this topic =/
I hope that I gave a somewhat good summary of your questions?