Straight to the points:
1) You can configure RadEditor through its ConfigFile.xml / ListConfigFile.xml files as demonstrated in the following help article: Set Properties Via Config File
To change the toolbar mode from Default to ShowOnFocus, PageTop or Floating, update the value of the following tag:
2) I agree with you but this is the way to enable the web part by clicking on its dropdown menu and selecting edit webpart.
3) This feature is still not implemented. Right now the Telerik RadEditor for SharePoint 2010
web part is available in the Miscellaneous category of SharePoint Site only. This feature is already logged in our ToDo list and we will implement it for one of the next versions of RadEditor for SharePoint 2010.
the Telerik team