Zendesk Support Custom Objects for Displaying data from ERP via API

Hi,

In terms of using the custom objects to get the information from ERP, I was already given information mentioned on this page https://support.zendesk.com/hc/en-us/articles/4408834725402-Sunshine-custom-objects-guide-for-admins 

I had a follow up question on this  - is there any limitation on how we can use it or not use it to display the  information on an agents workspace ? Can we customize the existing Agent Workspace user interface to use those objects as we like ? 

Also, is there any existing app or a solution that we can leverage for doing this ?

Thanks,