The five founders are all over the world. The US, UK, Russia and French Polynesia. Most of the employees are in the US and there are volunteers and advisors all over the world as well.
I don't work for Blue Frontiers but I support the project so much that I retired and moved to Tahiti to offer any support I could give and to have a front seat of history being made.
Current minimum for the pre-sale is the equivalent of 40 ETH in ethers or BTC. Or 100 ZEN. During the public sale the minimum will likely be 1 ETH.
Blue Frontiers is currently incorporated in Singapore but that could change. Much of the work is being done in the US, mainly the Silicon Valley area.
Last numbers I saw were about $200k per person on average to have a home on the seastead. Of course that's the average so some places may be single person bungalows that cost a lot or apartment units that cost less. The hope is to develop mass production techniques that can put out cheaper and cheaper units giving the average person the opportunity to have an oceanfront home much cheaper than on the land.
The Pre ICO started about a week or two ago. The full ICO will likely be in early June as they work on running security checks on the smart contract with many eyes including a third party team who is well known for securing ICOs (I'm not sure of the name right now).