I think you might want to question your premise about getting a visa being hard. If you have money to invest you can try an investment visa; if you have skills then QMAS. If you register a company and can employ others (including locals) then it might be able to sponsor you eventually (probably not straight away). My understanding is that tax rates in China are higher than HK, so not sure why you'd want to live there. Do you have a visa to live in China or residency rights?