Police are also appealing for information about items believed to have been in Miss O'Callaghan's handbag.
The buses will then travel down Callaghan Square and Lloyd George Avenue, heading to Cardiff Bay.
Taxi driver Christopher Halliwell, 47, from Swindon, has been charged with 22-year-old Miss O'Callaghan's murder.
He entered Parliament after winning Jim Callaghan's old seat and doubling the majority in June 1987.
BBC: News | UK Politics | Alun Michael: The new Welsh Secretary
Police have said they are "very close" to identifying the whereabouts of Miss O'Callaghan.
Miss O'Callaghan's body was formally identified by Pete Shawe, the partner of her mother Elaine.
BBC: Sian O'Callaghan 'died of head injuries', inquest hears
Sian O'Callaghan is likely to have died of head injuries, an inquest has been told.
BBC: Sian O'Callaghan 'died of head injuries', inquest hears
He was jailed at Bristol Crown Court on 19 October after admitting Miss O'Callaghan's murder.
Christopher Halliwell led police to Becky Godden's body shortly after he confessed to killing Miss O'Callaghan.
Stand-in captain Donncha O'Callaghan described the Lions' final warm-up game as "full-on" and "manic".
Callaghan, of Ivy Bank Lane, Keighley, admitted manslaughter due to diminished responsibility at an earlier hearing.
BBC: Haworth man Clement Callaghan, 80, jailed for killing wife
Hill is the first full BARLA tourist from York Acorn since Darren Callaghan in 1998.
Lions duo O'Gara and Donncha O'Callaghan also made their first starts of the season.
The last Lib-Lab pact, in 1977-78 during the premiership of James Callaghan, ended in tears.
Det Supt Steve Fulcher said he was "quite clear" that one of the bodies was Miss O'Callaghan.
Callaghan's first round throw in the competition reached 22.75 and left her behind Tunisia's Ayda Sidhom (24.02).
Among the academics that gathered for the debate on Wednesday was daughter of Jim Callaghan, Baroness Jay.
BBC: NEWS | UK | Education | Adults 'lose out over jobs focus'
Munster fielded Lions centre Keith Earls and lock Donncha O'Callaghan in a team that was also at half-strength.
Fitzgerald, O'Driscoll, Tommy Bowe, Donncha O'Callaghan and Jamie Heaslip retain their starting roles from the South Africa defeat.
Halliwell also led police to the body of Becky Godden shortly after he confessed to killing Miss O'Callaghan.
Miss O'Callaghan, 22, had not been seen since she left a nightclub in Swindon early on Saturday morning.
In 1996 Batista brought on Jeremiah O'Callaghan, now JBS' investor-relations director, with the charge of taking JBS global.
Jamie O'Callaghan crossed for Quins but David Williams, Brett Stewart, Jamie Lyon and Steve Matai sealed the win.
The court was also told how Callaghan's GP had described the killing as "quite astonishingly out of character".
BBC: Haworth man Clement Callaghan, 80, jailed for killing wife
O'Callaghan set up Randall and then scored a try of his own after good work by Mike Burnett.
Van der Westhuyzen's break-out with seven minutes left was halted initially by superb tackles from Worsley and O'Callaghan.
Wendy Callaghan, a mum-of-two from Bedwas, is one of 500, 000 deaf or hard of hearing people in Wales.
"This latest bailout makes a mockery of EU state aid rules, " said Ryanair's head of legal affairs, Jim Callaghan.
Christopher Halliwell was sentenced to life with a minimum term of 25 years for the murder of Sian O'Callaghan.
Mr Headley added that Miss O'Callaghan's family were coping "as well as you or I would in these situations".
BBC: Police 'very close' to finding missing Sian O'Callaghan
应用推荐