Are there any issues going live with payroll first (without finance) in the cloud?

Are there any issues going live with payroll first (without finance) in the cloud?  Client would like to bring payroll and HCM live before financials.

I know that the cost allocation usually follows the accounting KFF and that I have to map the payroll to the general ledger in EBS.  I am assuming it is the same in the cloud?

This would mean that a shell of the financials should be setup, but is it absolutely necessary?  Also, are there any other items that need consideration?

Example:

I know that I can do the enterprise work structure setup through HCM, but is there anything that must be in place for finance before using payroll?  For example, if Finance does the setup and loads the configuration without HCM completing all the necessary jobs and positions information (i.e., KFF stuff if needed), then HCM is hosed and cannot add segments to the jobs or positions.