no, you fill it in as non-residents.... otherwise, you may be liable to pay canadian income tax (if they think you are resident.... and by filling in customs forms as a resident, that is what you are declaring)
no problems at all with customs.... i've been doing it for 17 years not. why in the world would they give you a hard time?
it isn't illegal for canadians to live in other countries, so why would there be a hassle?
usually goes like this:
hand passport over at counter
"how long have you been away from canada?
"i don't live in canada"
"oh, where do you live?
"hong kong"
"how long have you lived there?
"almost 17 years."
"how long will you be in canada?"
"one month"
"what is the purpose of your trip?"
"visiting family."
"ok, here is your passport, have fun!"