I suggest use Inline Entity Display

Description"

Overview

Make available the fields and text properties from referenced entities into the parent entity template and the manage fields display overview. Drupal standard entity display:

Node

• title
• field body
• field reference -> default formatters

Also if you want have better entity reference selector use Entity Reference View Widget module.

According to the description of the References Tabs module

This module allows to render nodes referenced via a node reference field in tabs, with node titles as tab titles and rendered nodes as tab content.

it is only support Nod referenced not entity reference ,you can see here that it is not support entity reference , you can change your field from entity reference to node reference type.