100% This isn't a neighbor issue - this is a safety issue. The neighbors may or may not be reasonably confident that their dogs are safe around kids (it doesn't sound like LW has even asked?) but even then, they sound like good enough dog owners they wouldn't leave a five-year-old unattended with them! And if LW's kid gets hurt, it'll be blamed on their dogs. If LW won't do anything they've got no choice but to escalate for the dogs' safety as well as the kid's.