A communications system may include end-user devices (EUDs), a communications network, and a message processor. A message parser determines, from a received message, a message originator EUD having an associated originator message channel format, and at least one intended message recipient EUD with an associated recipient message channel format. A message channel database includes respective different message channel formats for different EUDs. A message recaster cooperates with the message parser and message channel database and transmits at least one recast message based upon the received message, which may include a corresponding recipient message channel format with a corresponding Internet Protocol (IP) address for the at least one intended recipient EUD.