With Fox Sports creating a new dedicated League Channel, there is actually a really strong opportunity for multiple Nines tournaments in the Australian and UK off seasons.
Fox will want any fresh content they can get for this dead window which would help the RLIF secure some funding for such a concept.
As mentioned multiple times already in this thread I agree with the concept of allowing NRL/SL players to take part in such a circuit if they want (and can negotiate the opportunity with their clubs) whilst mainly focusing on amateur and semi pro players.
Ideally such a circuit should require teams to contain a minimum number of resident players per team. If the aim is to use this to help the emerging nations grow then they need to give locals a chance to make the side.
In terms of location a 3 game circuit works best when starting. One in Europe, one in Oceania and the last wherever wants it.
We can then have a certain number of teams play in all 3, and then spots open just for local sides (ie. Belgium might only play the Europe leg, and Vanuatu in the Pacific, but Australia, NZ, PNG and England play all 3)