The timing for reviewing a case already concluded and the rare step of inviting western media suggests narrative play.

China did warn of severe consequences. At the very least, China wouldn’t have allowed a low level official to determine international discourse. Perhaps China is at least suggesting the same thing to Canada -- don't allow a low level process to interfere with high stakes conversation.

Not sure about China but in many Asian countries drug-related crimes are considered to be very, VERY serious, and often lead to death sentencies: Vietnam, Thailand, Phillipines all have very strict laws here.

For non-foreigners this normally means death sentence. Foreigners do sometimes get some sort of special treatment.

Doubtful. In China (and majority of east and se asia) severe drug penalties are common. Do not touch drugs in the areas. A friend from Shanghai once told me that he has heard (apply huge grain of salt) that there are 5000 drug related executions in China yearly - mostly in the southern and western parts of the country.

It is probably his original sentence was a show of clemency towards canadian citizen which they now take back.

Maybe, maybe not. I do believe that if he wasn't Canadian, we wouldn't be hearing about it.

They held a one day retrial after he requested a retrial of his 15 year sentence a while back.

Probably not. Death sentence for drug-related crimes are very common in China. A British citizen got death sentence too a few years back.