Q: Can a minor get convicted far assault and robbery because someone was robbed and gave police a description of just facial hair

A:There had to be something more than “facial hair”. The police report just cannot read, the actor is described as, “facial hair”. If what you mean is a weak description, yes, it is possible to be arrested, but those kind of cases are often beaten at trial. If the police were on the fence about arresting him, the fact that he has priors may give them reason to do so. This is not fair but it happens. I would have a lawyer review the case.