Yes, but be prepared to rely on WiFi. You can get charged roaming fees so keep your phone in airplane mode. Make sure any directions that you need are saved or download a city map beforehand.
Right now, $1CAD is $0.77USD I would recommend having at least $50CAD since some places will not accept USD.
Yes. Don’t be Jackson, double check that it isn’t expired at least 2 months before you leave. Or better yet, check it now. For more info on documents you will need, check out below. https://travel.state.gov/content/travel/en/international-travel/International-Travel-Country-Information-Pages/Canada.html
Yes, you should be able to get and drive a rental car in Canada no problem. Heads up for all our US friends and family, they use kilometers not miles.
This website has great information to answer your questions. https://www.canada.ca/en/immigration-refugees-citizenship/services/visit-canada/entry-requirements-country.html