I was referring to the part about the need for customs forms. The requirement about putting the word Canada into all-caps is true as you indicated, although the actual regs appear to say that the entire address, not just the word Canada, must be in all-caps.
The Canada Postal Guide says:
…Addresses should be written in upper case; however, mailers may wish to use lower case due to individual preference or other considerations. …
and
…Canada Post encourages all mailers to respect the wishes of customers in matters of format. The Canadian Addressing Guide has taken care to accommodate the requirements of the English and French languages by recognizing and accepting the use of upper- and lower- case characters, including accents, as well as the full spelling of and punctuation between addressing elements…
Now, that is from the instructions for Canadian mail within Canada, but I’d be surprised if it was different for mail coming in from elsewhere.