I want to customize the SharePoint 2013 online(office 365) "About me" linked page (personimmersive.aspx) to a custom look and feel.
Even clicking on any SPUser name, for ex in a list item modified by is "John Smith" if we click on it goes to about me page.
This page resides under mysite but I cannot see this page is SharePoint 2013 designer to edit, but modifying SharePoint pages in designer is not always the best way. Can I just create a new page and redirect all Profile page request to that custom page? IF I create app parts and edit the page I cannot edit the top portion of the page.
redirecting may not be a feasible approach, specially on the online versions
you can try to take advantage of web parts and css to do what you can
http://weshackett.com/2014/04/office-365-new-profile-page/