Sure. On the point about what to do to protect citizens, the Chinese government doesn't recognize dual citizenship. As a practical matter, I think probably the most urgent thing to do is to assess on what status dual citizens are in Hong Kong, meaning if they've entered Hong Kong on their Hong Kong status rather than their Canadian status. I don't know what mechanisms are available to change that, but at least it gives the Canadian government a slightly superior claim to those people in defending their interests.
I think making it very clear to Beijing that any efforts to deny people the ability to leave or reunify with family members would be an issue of the highest concern. Let's recall that the Chinese government has detained and held for decades people who are citizens of other countries and simply refused to acknowledge their citizenship and, therefore, the ability of representatives of those other governments to have access to them.