How can I redirect user to the custom profile page in SharePoint online? The ProfileRedirection delegate control cannot be used, because it is a farm scoped control. It looks like I can use JS to find and replace links, but I don't like to use this approach. Any ideas?
The customization options you have with Office 365 will prevent you from doing a sophisticated solution on the server side. You cannot customize or replace the profile redirection control like you can on premises. That means that you either need to control all of the links that send them to the profile page, or use client code to replace the destination with your custom destination.