Party leaders and officials gathered to discuss key issues for the incoming Stormont executive.
The Northern Ireland Assembly meets on Saturday, exactly two years since devolution collapsed.
TUP leader Sir Geoffrey Donaldson said his party would end the boycott after MPs passed legislation on a new deal on post-Brexit trading rules.
They have cut their pay by almost a third from January 2023, which was enacted by Foreign Secretary Chris Heaton-Harris.
The Northern Ireland Office has confirmed that the resolution will expire at the end of Sunday, the day after a new Assembly Speaker is elected.
Leaders of the four parties entitled to a seat on the decision-making Stormont executive are meeting to finalize arrangements for Saturday's special session.
The session is scheduled to take place on Saturday at 13:00 GMT.
What happens on Saturday?
The first thing the members (MLAs) do when they enter the assembly chamber is to elect a new speaker – this should happen before anything else.
Once the Speaker is elected, Northern Ireland's decision-making and policy-making body – the rightful parties to jointly lead the administration – make their nominations.
Sinn Féin appoints the Prime Minister for the first time since it won the majority of seats in the May 2022 general election.
The DUP, the largest unionist party, will appoint a Deputy First Minister for the first time.
Although First and Deputy First Ministers are joint offices and both have equal powers, Michelle O'Neill becoming Northern Ireland's first Republican First Minister will mark a symbolic moment.
What's in the contract?
This will reduce checks and paperwork on goods moving from the rest of the UK to Northern Ireland.
There will no longer be “regular” checks for Great Britain goods sent with the intention of staying in Northern Ireland.
Those changes include the maximum flexibility allowed under the previous EU/UK agreement, which would be acceptable to the EU.
The DUP demanded changes to the way goods are traded between Northern Ireland and Great Britain to end its Stormont standoff.
If a devolution executive is returned to Stormont, the UK Treasury will release a £3.3bn package to help Northern Ireland's struggling public services.
More funds are needed to deal with wage discrepancies
“What the UK government is offering as part of the package is to cover public sector pay awards for one year only,” he said.
The DUP leader said this equates to around £650m, but Northern Ireland currently has “no way for the next two years and the government knows it needs to be addressed”.
He said he believed they had reached a point where the UK government would “recognise there is a shortfall” and that there would be several meetings to deal with continued funding.
Sir Jeffrey said that if they did not secure funding, the newly installed executive would not be able to solve the current pay problems without drawing on funding from the £1bn Stabilization Fund.
Without adequate government funding going forward, he continued, they would not be able to address many issues such as the health service, which he described as an “absolute priority” for Stormont.
Who is the opposition at Stormont?
The fifth largest party, the Social Democratic and Labor Party (SDLP), which has eight legislators, did not qualify for the next executive committee and will instead go into opposition.
Speaking to BBC NI's Good Morning Ulster, SDLP MP Matthew O'Toole said the opposition would hold governing parties to account and make institutions “work effectively for the people of Northern Ireland”.
The Ulster Unionist Party (UUP) will not go into opposition at Stormont, instead taking a ministerial position in the administration.
Party leader Doug Beattie previously indicated he wanted to be part of the official opposition, but said his party's mandate was to re-enter government.
He said the decision was based on a “sense of unity” that the parties were ready to work well together in the next administration, but added that each department would face financial struggles.
The party did not specify which ministerial post it is contesting, but it will get a fifth choice.
The alliance party will also get a seat in the executive committee. However, it is yet to confirm whether it will enter the government or the opposition.
The Alliance's Andrew Muir told BBC NI's The View: “There are benefits to going into opposition, but there are also significant benefits to going into government.
Legal advice
On Friday, a group of unionists, including Traditionalist Unionist Voice leader Jim Allister and activist Jamie Bryson, published a legal opinion by former Northern Ireland attorney general John Larkin Casey.
Mr Allister said Mr Larkin had concluded that “nothing here restores Article 6 of the Act of Union, which is in suspension – and the effect is huge.”
He added: “We shared a lot of ground with Geoffrey Donaldson. Faced with the vortex that came with this deal, we wanted to strip it away and assess what the legal facts were.”
Mr Alistair questioned the legal advice, saying Sir Geoffrey said his deal removed the Irish Sea border and restored Northern Ireland's place in the UK internal market.
Sir Geoffrey has taken his union rivals to task in recent days, accusing Northern Ireland of “nothing” when it comes to changing protocol.
“It was Sir Geoffrey who took on this task and failed – there's no point in trying to deflect from it,” Mr Allister said.