Red flags here. There are umpteen local design companies more than capable of doing 12 villas. This could all be done remotely as well. The cost of making the visit, even if you think it is genuine, is outweighed by the risks of not getting the contract.
A usual practice here, if there is no cost to the client, is have a beauty contest, for as many companies as possible that you can persuade to submit a design. One where all 'bidders' submit concept designs, and the client just picks the ideas that they like, and give the work to someone cheaper locally. Unethical? Yes. Common practice? Yes.
Also, if there is a company Wuhan Construction Engineering, they will have a web address and emails that end with .cn and not 163.com.
The very least you could do is find a website for Wuhan Construction Engineering and email them about Mr Liu's bona fides.
But like I said, it is not worth the risk, and even if genuine, and you do win this contract, it is unlikely that this will lead to other work in the Chinese market. The other thing to consider is that Chinese design tastes are different to Western, the main thing lacking here is functionality. Form outweighs function, they may just want to poach a few functional ideas from the whole design.