Although the standard is the perception of a layman, where no reasonable juror could find substantial similarity in the allegedly infringing content, judgment as a matter of law for not stating a claim is appropriate.
Although similarities in unprotectable elements of the two works can be probative of allegations of actual copying, striking similarities in the concept for the protagonist do not make the superficial similarities in the protectable expression a violation of copyright.
http://www2.ca3.uscourts.gov/opinarch/172023p.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.