2017-04-18 : Any change to a land’s type or abilities gained by a land can affect the types of mana a land can produce.

2017-04-18 : Naga Vitalist checks the effects of all mana-producing abilities of lands you control, but it doesn’t check their costs or legality. For example, Spire of Industry says “{T}, Pay 1 life: Add one mana of any color to your mana pool. Activate this ability only if you control an artifact.” If you control Spire of Industry and Naga Vitalist, you can tap Naga Vitalist for any color of mana. It doesn’t matter whether you control an artifact, whether you can pay 1 life, or whether Spire of Industry is untapped.

2017-04-18 : Naga Vitalist doesn’t care about any restrictions or riders your lands put on the mana they produce, such as the one Cavern of Souls has. It just cares about types of mana.

2017-04-18 : The types of mana are white, blue, black, red, green, and colorless.