Best way to integrate FSC with Back Office capabilities?

Hi there,

We are designing a new FSC (front-office) Architecture and would like to have it integrated with our back-office systems. What would be the recommended way of doing this according to FSC best practices?  A bit of context:  

• We have multiple lines of business
• We want the new Architecture to be Customer-Centric (So when the customers contact us we will know who she/he is and then see all the products/cases they have with us)
• We want the Front-Office stack and Back Office staff to be different teams 
• Time to resolution should be optimized
• Front-office team members should easily know the status of a case (if the case is now being handled by the back office team)
• We want to keep FSC as standard as possible
• If recommended we can use DPA and Salesforce Workflow capabilities for automation.

I would like to know what's the line between what should be handled by FSC and what should be better handled by our existing Back Office systems (that are going to be refactored as well).

Any help would be much appreciated.

Thanks