And the fact two people are taking the selfie at all is bizarre.

• One – Obvious.
• Multiple but spaced out over time – Maybe strange, but makes some sense if you want to use them locally and don’t want to wait to have it sent to you.
• Everyone doing it – Makes sense as a humorous gimmick.
• Exactly two people out of a group of five?
  • As you said, same phone, so zero technical quality difference.
  • Basically the same angle.
  • The rear one will probably capture the first phone in her shot.
  • Looks stupid as fuck.