Overall, the mod is great and a lot of fun - Thank you.
I do have a couple small suggestions:
1. Some of the wonders in the Prehistory era give bonuses to resources that you are unable to see (The Totem - deer, several wonders for stone). It might be more beneficial to make it so you are unable to build those wonders until you can see the relevant resources. This way you aren't building the wonders in a city that won't receive much of a benefit from them. It might even be best to not have any wonders that improve the value of a resource until after you can build settlers and found cities.
2. I would have all/most the luxury/bonus resource discovery techs placed before the settler tech. This way you can create cities in ideal locations. In most of my test games, by the time I get to the settler tech, my production/happiness is high enough that I create all of my additional cities immediately. If you wait until you've researched more techs to see resources, the AI has already settled in many areas and you've lost out on many turns of population growth. Some of the resources definitely should be available later in the game from a historical perspective, but others, such as stone, should be available much earlier.