Hi Dennis,
It is possible to export data from the SuccessFactors HCM suite, which can then be imported into SAP HCM. These are two different processes, since once you have the data exported you need to have a way to import it (e.g. LSMW or custom report).
Regarding the data you are exporting, it depends on the module of the suite. Most of the data can be exported from OneAdmin in CSV format, but it really depends what you want to export.
It is also possible to use Ad Hoc Reports or leverage the SuccessFactors API to export data to SAP HCM.
Best regards,
Luke