Cloud receiving employee data rather than system of record?

Summary

Pros and Cons - Importing person and assignment data to Cloud from other systems

Content

We have 4 acquisitions in Europe and our original plan was to migrate employee data to HCM Cloud and then interface the data back to the payroll vendor.  We found that these countries (small businesses, < 500) all are using HR, time and attendance and payroll on the local payroll system and will continue to use the same payroll.  So, by moving the data to the Cloud, we are disrupting their local processes and will result in users needing to do maintenance in two systems because some information will never be in Cloud (including Benefits, Pension, time and attendance).