What to wear for invited talk in Canada
Note: I am not Canadian, so this may be a bit off. However, I do hire post-docs fairly regularly into a research group at a US National Lab. 

First - for an official post-doc interview your proposed attire seems appropriate. Dress slacks rather than jeans would be an upgrade, but probably not necessary. (Note that standards in the US can vary regionally, I'd assume similar in Canada. What is needed in Toronto might be different than Vancouver or Saskatchewan. An interview in New York City is different than Denver.) 

As an added comment, you should treat this as a job interview because it definitely is one. While it may not be the formal interview, they have asked you are going out to give a talk. Any impressions from this visit will apply to a more formal interview. If it goes well, there may not even be a separate formal interview. Good luck.