We're still waiting for word on whether or not Luka and Stjepan will be there for those parts of MDP that don't conflict with their touring schedule. But they are in Australia and New Zealand for the first few performances, and in Southern California for several performances of the second run.
Right now the only "regular" tickets available for sale are for Rocket Club members; and the high end tickets for the first few rows as far as we know.
During an ABC News interview done sometime late Jan or early Feb 2015, Luka says (near end of interview) they will be playing with Elton at Caesar's Palace at some shows in March and April. No more details than that.