Dear Swetambri, ideally UML plays its role after specifications/requirements. But UML can contribute achieving these properties by Analysis using UML. UML can be used as a tool for analysing the fitness of the specification wrt all those properties mentioned by you. Here below, I am mentionaing few aspects of various UML models and property covered by them ...
1. Completeness, - Use Case diagrams
2. simplicity, minimality - using stereotypes of models(use case,class diagram) like uses/extends or customed stereotypes.
3. clarity,overspecifiaction, contradtiction, ambugity tolereance - activity diagrams
4. Formality, releveance, Constructibility, Comprehensibility, applicability, Extensibility, rigour ,usibility,Noise,silence, usibility - By using Class diagrams/Object diagram

see UML is a generalised notation with some features. by understanding & using these features properly, UML can help you to test these properties of your specification. Definitely for many properties,you have consider features of the technology to be used in addition to UML.

Further, I will looking forward to your response if I have understood and replied your query correctly or not.Enjoy!