Any insights on moving multiple companies to a single company structure?

JDE Enterprise One 9.2

JDE OneWorld Xe

We are working with multiple business units from being set up as separate companies to being consolidated into a single company with multiple branches. We are working through a phased upgrade from Xe to 9.2 and will be mirroring changes in both environments. We've been working with external consultants on the mechanics of the change. My query to you all is if you've done company consolidation what were some unexpected issues, and are there any best practices you can share from your experience? What were some other implications of moving from separate companies with branches to a consolidated company encompassing all