Rule one of having multiple passports: Make sure all the names match.

Rule two: follow rule one.

All my passports and travel documents have my surname, English given name, Chinese given name in the same order and spelling.

Yes I realized that's an issue, didn't think much about it when doing the legal name change in Canada and since having obtained the Canadian passport I have not traveled using the Taiwan one.

The flight time is in about a month from now, should I just keep it simple and bite the cost for a China Visa and travel with a single Canadian passport only?

I would contact aa and see what they suggest. Perhaps they could add a note to your pnr about your Chinese name.

I would do exactly this--get a visa and travel on the Canadian passport only. It will circumvent all manner of potential troubles.

Why not call aa first?
-he has the legal right to enter China
-the border control people don't care about his plane tickets
-the only potential hiccup is aa front line employees
-the name change thing is pretty common
-wouldn't you explore all possible options before spending the time and money to procure a visa?
-his hrp is far better than a visa; he should use it

Sure, he should rectify the name issue for future trips, but there is nothing remotely dodgy about his status wrt the immediate trip.

Dealing with Taiwan passport issue is very time consuming from Canada.

AA is new at flying to China so I would minimize any irregularities for them to make mistakes.

~10 years? That's ancient history in China.

Adding note to pnr should be easy.

My trip is BUF-DCA on US then DCA-ORD-PEK on AA and return.

At what point does the passport need to be checked? I think I can get the baggage interlined and all BP printed at BUF but will the agents at BUF/DCA check passport? I'd rather deal with AA agent at ORD since it's more international and they should know more about the matter.

Additionally, wouldn't the border agent at PEK check my boarding pass (which has English name) while I also hand over my taibaozheng that has a different name?

I'll call AA and explore the options, but would probably still get a visa to have a peace of mind. Are all China visa 10 year validity now for Canadians or is that just a USA agreement?

Also valid for Canadians but it is apparently "up to 10 years" or your passport validity, whichever comes first. But not many data points on this question.

Hah ok, my passport expires next year so I'm looking at a new Canadian passport + China visa + possible rush fee totaling $300-500 then if I want to get them all done in a month and get the maximum validity.

What's the China visa process? I read it's 4 business days for normal service in Toronto, do they take the passport away while processing?

240 St George St., drop off properly filled out application + Passport and get it back the next day.

It is the US Air agents at BUF and or DCA that I worry about.

Yes my concern as well, tho the BUF is a separate ticket so likely no worries there. What are my rights in terms of a passenger should something like this happens? Can I request them to fly me to ORD and then let the ORD agents check again or will they just deny boarding regardless.

Been there and done that for cheaper tickets and airport parking.

If your BUF ORD ticket is separate then the AA/US staff's document check is to make sure you are who you are.
BUT
You wish to interline from BUF to PEK which might bring up issue for the US agents tagging your bags to PEK might not be familiar of these multi-nationality, multi entry requirements.

I had issues using HRP out of BUF before as well as using a non-Canadian passport and APEC which give me visa free entry to many SE Asian countries.
NW used to be great when most of their intl was TPAC and have very knowledgeable source of entry requirement that local agents can check with. It was not the same once DL took over and have no idea what HRP and APEC cards are. I would be uncomfortable with US agents who are not familiar with international flights and adapting to a new AA?US way of doing things.

Are you now really without any Canadian middle name and also the AA ticket? Having any given name overlap can be helpful.

I'm afraid for Taiwan and especially China, English is not official and thus name is only a derivative. AKA may be all Taiwan's govt can do.

That's why some overlap is useful. Months ago a HKer lady called onto a Los Angeles Cantonese radio show asking for help. She married a Westerner decades ago, didn't keep her maiden name or Chinese given name on any doc, and worse, "corrected" her DOB in America! She had properly maintained a HRP, but she had trouble boarding a USA-China flight!

(Ticket/itinerary breaking in a "third country" may just be the best solution!)

I'm afraid nobody on the phone can affect anything at any check-in counter.

Exactly. It isn't a gateway with Chinese-proficient agents. Get there early and most likely you can resolve the validity/legitimacy of the TBZ. But add these name issues it's a whole new thing.

Most likely not. China does require APIS and AA should probably transmit TBZ info and your Taiwanese Latin name, but failure probably won't cost you much trouble compared to denied boarding at DCA.