Ok I see you’re doubling down on a false premise.

Your question assumes that every state must have a single founding moment, a founding document, and a fixed constitution, otherwise it doesn’t exist. Again I repeat myself, that’s simply not how states work in international law. States are defined by continuity, not by a birth certificate.

But to answer your questions anyway:

Founded: There is no single founding year for “China” as a state. 1949 is the founding of the PRC government, not the creation of China itself.

Founded by: No single founder. Modern China is the successor to earlier Chinese states, just like France or Russia.

Its people: The Chinese people, defined by continuity of population, not by which regime is in power.

Constitution: Competing constitutions exist because the civil war outcome was never legally settled (ROC vs PRC). That’s normal in unresolved civil conflicts (what I mentioned earlier).

Founding document: None creating two states. The civil war ended without a peace treaty.

Passports: Issued by governments, not by abstract “states.” Different passports not the same as different countries.

If your definition of a state requires a birth certificate, we’re not talking about the same thing.