In Windows 10, you can make the operating system to search for certain file types or prevent the search feature from accessing them. This post explains the procedure in detail.
In Windows 10, Cortana can only be integrated with Bing and Microsoft Edge. The server-side part of Cortana is locked down. You cannot change the search engine in Cortana to Google or use alternative web browsers for web links. This post explains how to Make Cortana open links in the default web browser.