All other seats on the plane to New Zealand have been finalised with Kidney adding five new faces to his original touring party.
Ireland fell 29-28 to the Barbarians on Tuesday night but Kidney saw enough in the form and fitness of Ulster flanker Chris Henry and Connacht prop Brett Wilkinson to include them in the party.
The additional trio are Connacht's Mike McCarthy, who is covering for O'Connell, Ulster scrum-half Paul Marshall, in place of the injured Isaac Boss, and prop Ronan Loughney, a potential stand-in for Leinster's Mike Ross.
Despite losing in Gloucester, Munster wing Simon Zebo, 22, and Ulster flyer Craig Gilroy, 21, showed their worth to the side with three tries between them.
Munster's Keith Earls scored one of his own while club-mate Ronan O'Gara converted all four efforts.
Uncharacteristically for a Barbarians match, the result was determined by a penalty kick from Barbarians, and former Leinster, fly-half Felipe Contepomi two minutes from time.
The invitational side set to rights their 57-26 loss to England on Sunday with tries from Treviso lock Cornelius Van Zyl, Iain Balshaw, Paul Sackey, Mike Tindall and Contempomi's four goal kicks.
Ireland's tour of New Zealand sees them play Test matches in Auckland on June 9, in Christchurch on June 16 and in Hamilton on June 23
Forwards: Rory Best (Ulster), Sean Cronin (Leinster), Declan Fitzpatrick (Ulster), Cian Healy (Leinster), Jamie Heaslip (Leinster), Chris Henry (Ulster), Ronan Loughney (Connacht), Kevin McLaughlin (Leinster), Mike McCarthy (Connacht), Sean O'Brien (Leinster), Donncha O'Callaghan (Munster), Peter O'Mahony (Munster), Mike Ross (Leinster), Donnacha Ryan (Munster), Mike Sherry (Munster), Dan Tuohy (Ulster), Brett Wilkinson (Connacht)
Backs: Darren Cave (Ulster), Gordon D'Arcy (Leinster), Keith Earls (Munster), Rob Kearney (Leinster), Paul Marshall (Ulster), Fergus McFadden (Leinster), Conor Murray (Munster), Brian O'Driscoll (Leinster), Ronan O'Gara (Munster), Eoin Reddan (Leinster), Jonathan Sexton (Leinster), Andrew Trimble (Ulster), Simon Zebo (Munster)