Test players Joe Powell, Pete Samu, Luke Jones and Matt Philip have been picked in the initial squad, along with uncapped Rebels duo Billy Meakes and Angus Cottrell.
The Baabaas will take on a Fiji XV at Twickenham this weekend before travelling to Brazil to take on the South Americans on their home soil in a week's time.
Their final match of 2019 will be back in the UK, against a Wales XV at Principality Stadium in Cardiff.
