Option to reorder task lists within milestone is not available. However, reordering the task lists in Tasks & Milestones − −> Tasks section will be reflected within the milestones, too.
Dependency can be set only between tasks, that too within the same project.
You can see all the overdue milestones across all projects from Task & Milestones > Milestones in the Overdue Milestones section.
If you want to see all the overdue milestones of any particular project user, use the Filter option in the My Milestones section.
In Milestone Flag, choose the External option, if you wish to collaborate and display the milestone with client users. However, if you want to display only to your portal users choose the Internal option.
Go to Tasks & Milestones section of the project. And then click the Milestones link to view all the milestone types in that project.