The foursome all wrote to the national chairman and treasurer of the PDP saying they have all returned the money they received to the account of the party.
Abdulsalami Abubakar, chairman of NPC, said the accord was to promote peaceful electioneering.
We will not be distracted by the wishes and actions of detractors that wait gleefully but in vain for some kind of crisis to erupt between the Party and the PCC.
The Minister urged Nigerians to use the occasion of the celebration to reflect on the challenges facing the nation and the role individuals can play in addressing them.
2023: Massive crowd as Obi promises to end insecurity, unemployment, corruption if elected president
Mr Obi was in the state to honour the invitation of the Middle Belt Forum (MBF), organisers of the rally in solidarity with his ambition.
Mr Obi made the promise on Wednesday while reacting to the collapse of the national grid on Tuesday - the seventh time since the year began - throwing the nation into darkness.
Under this administration, the President has repeatedly made it clear that nobody is allowed to illegally carry AK-47 or any other automatic weapons and that they must surrender them.
APC to expand campaign council membership after sabotage threat, postpones inauguration indefinitely
This is coming after Northern aggrieved governors on its platform threatened to sabotage the chances of the party to win the presidential election next year over the exclusion of their nominees from the 422-member list.
The aggrieved governors who said it was not the first time the party's candidate, Bola Tinubu, offended them, resolved to work against the life-long ambition of the former Lagos governor to succeed Mr Buhari.