Determining an interim office location for the proposed Hampshire and the Solent Combined County Authority is one of a number of decisions that need to be resolved.
The statutory instrument legislation to formally establish the devolved authority is expected to be laid and debated in parliament in November.
A shadow board for the combined county authority is being set up with appointments from each of the constituent upper tier councils - Hampshire, Portsmouth, Southampton and Isle of Wight.
This board would make the decisions that need to be taken before the new entity is formally established in early 2026.
Southampton City Council's governance committee received an update on devolution at a meeting on Monday, October 27.
Devolution programme director Munira Holloway said alongside deciding an interim office location, temporary arrangements for matters such as IT, finance and HR systems needed to be addressed.
Ms Holloway said: "All of the people that are directly involved at the moment have the opportunity to put forward proposals and options around that.
"We have agreed independent assessment criteria because obviously these things are potentially somewhat controversial, and people have different views.
"We are working through an as far as possible evidence informed assessment criteria and then providing recommendations to chief executives and leaders on that basis.
"I think it is really important to say that all of those are temporary, so they are in no way pre-empting longer term solutions."
Elections for the regional mayor who would head up the combined authority are scheduled to take place on May 7 next year.
The mayoral combined county authority will have devolved funding and powers from central government, with a key focus on transport and infrastructure, skills and employing, housing and strategic planning, and economic development and regeneration.