EBS Diverstiture/Separation Question

My client is separating into 2 independent companies. Post LD1 we are going to have 2 separate EBS environments each housing each of the companies independently. We currently have open transactions eg Invoices with distribution  lines that cut across the balancing segments that belong to the 2 companies being split. What should be the best solution to provide to the business in this case?

We also have assets with split assignments. How should we handle the same?

Also we have shared services where the users can enter transactions for different OUs belonging to the 2 companies. Moving forward should  we just assign the users  relevant MO operating unit profiles that belong to relevant companies, and then post LD1 they can only see data for only their respective companies?...Please note after the cloning of the current prod environment and subsequent creation of 2 separate environment, setup and historical data of one company will reside in the other company.