A Bulldog will not be able to handle the strenuous hours of daily workouts a Border Collie requires. Research any breed thoroughly before getting use several different sources as well. What one person or even a vet says about a breed may be totally erroneous. If you are looking at a cross, research the breeds you know are in the cross to give you an idea of what you are getting. And bear in mind that small does not equal less energy.
Some giant breeds have lower activity level than many smaller breeds.
Size is not always relevant when it comes to how much energy and exercise a dog requires. Others require only a few minutes of going over with a brush once a week as well as regular attention to teeth, ears and nails. All dogs shed to some extent. Even supposed no shed breeds will lose hair. Hair falls out of follicles take a look at your own brush or how often do you pluck a strand off your jacket.