Of course it can be switched off.

Of course, use of the mixed mode (convection and steam) is recommended.

Absolutely not.  By using forced air (convection) as the cooking environment, flavours and smells do not mix.

If referring to frying large amounts, it is not possible.  There is an option to finish off “pre-fried” food (French fries). Pasties can be cooked in the oven with a similar result to frying, but not exactly the same.