You can't make a similar article because foreign investments are tighly controlled except for cases where business processes or IP can be studied and eventually expropriated.

No investment fund in the west would be able to just walk into China and start buying up real estate, infrastructure, and large private enterprises.

Foreigners cannot buy real estate in china.

Untrue. It depends on the city, but in Beijing you can buy (given the Chinese definition of buy anyways) a property after being resident for 5 years.

Can you buy a property without being a resident though? From a quick search, I found a site stating that you must live in the house and cannot buy one for other reasons.

This contrasts wildly with anecdotes I read about with Chinese investors in places like Vancouver.

No, you must be resident. Every city has its own rules though, I only know those for Beijing. There could be some second/third tier cities where speculation by foreigners is possible.

Why is China overflowing with investment money? Where does it all come from?

Simplification: When americans and europeans buy chinese products then china has dollars/euro and we have physical goods. Dollars/euros can only be used to invest into usa/european companies or to buy usa/european products.

On top of that: Chinese financial markets are strictly controlled and the rates of return on safe investments like bank deposits are artificially kept down. Chinese citizens have very few trustworthy investment options outside of housing or sole-proprietor entrepreneurship, and the latter is only feasible for the politically connected.

Are non politically connected Chinese citizens sitting on any money to invest?

As I understand it, China doesn't allow speculation in anything other than real-estate and Chinese can't buy property in China (it's more of a grant from the state).

So there's a lot of money that can't be invested locally or in financial vehicles (ie, 401k).

There is the Chinese stock market, but it’s lost most of its credibility as being heavily vested in insider trading.