Copilot Agents Wave 2

Hi there, after reading all the wave 2 announcements for Copilot, I'm interested to know more about the dependencies between Copilot Agents that are created in BizChat and Sharepoint and dependencies for Copilot Studio. The Microsoft release info online refers to a "lightweight" version Copilot Studio. My questions are: 

Is Copilot Studio needed to create Copilot Agents in BizChat and SharePoint? 

Is the Power Platform a hard dependency for creating Copilot Agents in BizChat and SharePoint?