You can use the Verizon Messages+ application, but the phone number associated with the application must be assigned to a VZW phone on your account. It won't be phone numbers assigned to the line of service for either the Ellipsis tablet or Jetpack. You can't send and receive text messages natively through the tablet or the Jetpack.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.