Hermosillo has an International Airport so it is possible to fly directly or with stopovers from almost anywhere in the world.
No, Hermosillo is just a small city with less than a million inhabitants. It is safe, especially in tourist areas.
In Hermosillo, as in the rest of Mexico, Spanish is spoken, however, being a city very close to the border with the United States, it is easy to find people who also speak English. French unfortunately is a little less likely.
The US dollar is accepted in some businesses at the exchange rate chosen by the business, so we recommend changing your money into Mexican pesos, either at the airport or at exchange offices of your choice. Unfortunately, the Canadian dollar is generally not accepted.
There are plenty of activities to do. We will also plan an itinerary for you to get to know the state, see the "Travel" section for more details.