My mistake, I meant Agility Team. You will need to scale these as required. They will be responsible for helping the organisation improve, and thereby create a better space for the Scrum Team.
I would disagree about the guidance on teams not being cross functional
An Agility Team consists of a Product Owner, Change Team, and Scrum Master. The team is self-organizing and cross-functional.
. The guidance regarding Domains is around the value proposition. It is the same principle that we coach in Scrum, with teams that can support the vertical slicing. I appreciate that the term Domain may confuse instead of make clear.
With the work spanning multiple sprints, I would encourage that this is treated like a very large Product Backlog Item (Epic), and decompose it down to the point where it is deliverable in a Sprint. You can size them, and in the sprint planning decompose and then burn them down. The main highlight is that it may take several sprints to see the effect of the change programme, and the metrics being used may often be a lagging indicator. This is where using a subjective measure as an interim sanity check may be viable.
The intention of the guide is to remind people that change is difficult, needs to be structured, and that using a template/cookie cutter approach may not deliver the profound change in organisational mind-set needed. If you bury yourself in the immediate numbers you may not even see the competition passing you by.