Is there difference in ICO price of RICO mint I, II and III like early adopter bonus
Here you go:
Sending XAU early or later on does not give any advantage as the rate will still be the same 1XAU = 8000XAUR.
However the advantage of investing fiat and other crypto early on, is the minting cost: Minting cost in RICO Mint I will be the lowest because for each mint the minting cost is greater or equal to the minting cost of the previous mint. For example here are the minting costs for Mint I and II:
RICO Mint I minting cost: 0.03638375$
RICO Mint II minting cost: 0.03812457009$
RICO Mint III minting cost will be greater or equal to RICO Mint II minting cost and so on.