Originally posted by Theodore Casser:
Regarding the second question - you need to provide whatever documentation you would normally provide for a project of this profile. If you decide that you do not need such things, then that's what you should submit. Likewise, if you feel you should supply copious documentation, then that's what you should submit. The idea of the project is to show how you work as a software architect and your ability to design a solution to their problem.
While I completey agree with Theodore Casser's opinion, I would like to add my 2 cents worth.
UML, being a modeling language may not competely convey all you wanted to say about your architecure. Patterns, being the choice of conveying reusable design artificats, it is better to document so that whoever implements this architecture, will be able to understand it better.