I work with this type of thing on a daily basis and
Seychelles has indeed become quite popular from where to trade with China. Hong Kong used to be popular for this (and still is), but compliance of a HK company has become a bit of a pain, and there is also an auditing requirement there that can add to the operating costs.
Regarding anonymity of a
Seychelles company, a register of members must be maintained in the
Seychelles by the local registered agent. However, it is not public record and is only open to inspection by members of the company. It will not be disclosed unless there is a order from a
Seychelles court to do so. Furthermore, there is a tax treaty between
Seychelles and China which is useful to have around depending on the circumstances.
Remember, your trading partners in China are going to have to be happy to pay invoices issued by a company set up outside of China. If not, and they want to be invoiced by a domestic company (because of exchange control hassles for example, or the [withholding] tax they have to pay in China if they pay fees for services provided by a company based outside of China), you are going to have to set up a local company in China also.
Please feel free to message me if you have any questions- happy to help