1. Do i get the choice to pick the International edition? (As I will be mainly using it in Hong Kong and Malaysia instead of in Canada)
If I'm not mistaken, based on the news spread over the internet, the United State and Canada will get getting the D820 model from Play Store which is NOT LTE compatible in Hong Kong and Malaysia. So no luck for you.

2. Will the adapter/charger cause any problem? as far as I know different adapter is used in North america compared to Msia & HK. Wonder if the charger will work in Msia/HK?
As simple as that. NOT compatible. You have to just pay few more RM to buy USB Charger local here or Hong Kong there.

and of course, warranty is based on the place you bought. LG/Google no offer international warranty. So is recommend for you either buy from Malaysia/Hong Kong when you come over here, since Hong Kong Play Store is started to sell.

Thank you for contacting Google. My name is Keenan and I will be further assisting you today. I would like to clear up some of your confusion.

1. The device is unlocked, meaning it has the same capabilities as the international version.

2. You will be sent the North American version having ordered from North America, but will have all the same capabilities as the international version.

I hope this helps clear some of your confusion. If you have further questions or concerns please respond directly to this email.

Regards,

Keenan
The Google Support Team