Moving to Da Nang August 26th - Would like to meet people there!

Search the Vietnam forums better, many discussions about "banking" and "unlocked".

AFAIK the 3 phone companies here are basically equivalent. Most people I know use Mobifone.

I got a Google mobile phone number before I left so I can use Google voice to make calls/text from here to the US. Calls going that way are free, and I can receive calls/texts. Probably to CA is same.
Google voice signup
You can also call people who use gmail with Google chat, call from Facebook to Facebook with Messenger, Skype, etc.
I have never had to make an "international" telephone call with charges.

Bring cash to squirrel away for emergency only AND use the ATMs. Emergency means like when you need to come up with a payment fast (like first + last + security deposit for apartment) or when your ATM card breaks. Cash must by like-new condition bills. USD might be easier to exchange than Canadian, dunno.
ATMs work fine, to minimize ATM fees and currency exchange rates choose your bank and credit cards carefully before you come. Nerdwallet has reviews.

Ok get to work, it will take a while if you need new bank accounts and google phone! Also I recommend getting motorcycle qualified on your license, so you are safer in traffic here, and you can convert into a Vietnamese driver's license. I had to take a weekend course in California.