Hello Jim,
If you want to implement also Mobile SSO for SAP Fiori you can use SAP Single Sign-On and the Mobile SSO solution based on One-Time Passwords and SAML. This scenario is available also for the SAP Fiori Client (native mobile app).
Here you will be able to find more details how to implement this scenario step-by-step:
Mobile Single Sign-On for SAP Fiori - Step-by-Step Guide
For this scenario you do not need the Secure Login Server.
Regards,
Donka Dimitrova