Four spots are up for grabs at each of the three qualifying venues with big-hitting Douglas star O’Keeffe tied for third behind Scottish amateur James Byrne at Western Gailes after a one under par 70.
Higgins hit a one under par 70 at Glasgow Gailes to sit just three shots behind leader Elliot Saltman and only one stroke outside the top four in tied 10th.
Tour rookie Caldwell fired a three under par 70 at Kilmarnock Barassie and shares 11th place with the likes of two-time Masters winner Jose Maria Olazabal.
The Clandeboye star is six shots behind leader Markus Brier of Austria but just three shots outside the qualifying places going into today’s final round.
Glasgow Gailes (Par 71) - 1 Elliot Saltman (Scot) 67; T10 David Higgins (Waterville) 70; T26 Brendan McDermott (Castlecomer) 72, Ronan Rafferty (NIr) 72; T53 Pat Murray (Am, Limerick) 75; T84 James Fox (Am, Portmarnock) 79, Jerry Scullion (Royal Co Down) 79.
Kilmarnock Barassie (Par 73) - 1 Markus Brier (Aut) 64; T11 Jonathan Caldwell (NIr) 70; T80 David Rawluk (The Island) 77; T53 Simon Ward (Am, Co Louth) 74; T91 Andrew Hogan (Am, Newlands) 81.
Western Gailes (Par 71) - 1 James Byrne (Am, Scot) 68; T3 Peter O'Keeffe (Douglas) 70; T66 Daniel Sugrue (Killarney) 77.
DNP: Colm Moriarty.