That’s nice since it's the historical order. But what do people do with Fields in the late game? Just abandon or delete them? And with Corrals after building Ice Houses?

I think the same things should be indicated by the same icons in both the Civilization Overview and Technological Tree, otherwise there’d be a confusing multiplicity of icon representations, and both would look aesthetically disconnected.

The structure tree mockup is also much better then the current one, do you have one for in-game ui as well? 

Farming is best until population becomes a limiting factor. Then comes corals, then ice houses.  

Yakhchãl I gives 1 food per second? But the goat cost 35 food and also gives 1 food per second. Inst much better to just have farms? legit question. not joking.