Okay... Yes didn´t think about it that way but you are right.
As rare as you see these team plays with their real national teams I guess you can almost consider these U23 teams as their senior national teams.
Exceptions are the "big teams" like Fiji, Tahiti, Solomon Islands etc.
Seeing the schedules I´m suprised that Tuvalu and Kiribati don´t send teams even though they send touch football, volleyball and basketball squads.