This is a big circus. The retired players are not really going to play. They are there
to sign autographs. That's all.
Each match is a best of 5 sets affair, a set of men's singles, a set of women's singles, a set of
men's doubles, a set of mixed doubles and finally a set of legends singles. So, the legends get to play only if the match is not already won and goes to the fifth set.
I also read that in each set, they plan to play tie breaker once the score reaches 5-5
instead of the traditional 6-6. Also, they plan to use "no ad" scoring.
Finally, to top it all, they plan to play 6 matches in each country (each team plays
every other team in each country) and then stop it abruptly. There is not notion of
two teams advancing to finals and the finals is non-existent. So, when the round
robin ends it is completely possible that no one knows who won the circus.
To put it in a nutshell, there is no real competition here by any stretch of imagination.