It is an unknown if any Irish left groups will sign up. So far, those with former/current Communist leanings seem more inclined to reject the idea – that may mean the Workers Party and CPI won’t be interested? Others are affiliated with the myriad of groups/Internationals claiming to be or descended from the 4th International and it remains to be seen if they join:
SWP International Socialist Tendency
Socialist Party Committee for a Workers’ International
éirígí attended International Marxist Tendency (but not members)
Some that claim socialism probably (do I mean hopefully?) wouldnt be considered for membership.
[Any leftie nerd that wants to add the affiliation of other left parties/groups or correct ones I got wrong, please feel free]