Hi Sergio,
Funny to hear that your client has invested implementing these and at the "same" time thinking of going to SuccessFactors. If the intent is to move to Employee Central and to have it being the System of Record, you would not really need to use the Fiori apps that you just implemented.
The SuccessFactors People Profile 3 and the new mobility is really UI5 and Fiori Like.
Regards,
Serge