Can losing baby teeth be the cause of bad breath in children?

Infection. Bad breath sign of infection, as in abscessed baby tooth. Or can be from poor oral hygiene. Need to gloss your child's teeth daily. Or can be infected tonsils/adenoids. Start w dentist. He may want you to see ent.
BAD BREATH. Not all the time. Make sure he brush his teeth regularly and check for infection.
Yes. Yes, sometimes. This may be due to an abscess formation under one or more of those baby teeth, or may be - sinusitis. One of the frequent reasons for children's halitosis is foreign objects in their nose- small kids sometimes push small objets into their nostrils, so we always recommend to visit ENT or pediatric doctor to examine nasal pass ways.