Moscow,
Russia 109012 Office 226,
15 Bolshoy Cherkassky Pereulok,
+7 495 772 4224 +7 495 627 0915
Our working languages are English and Russian. All correspondence and inquiries in other languages will not be answered.

Yes. The dates you specify is simply the time span during which you have to enter and leave Russia. You don't have to travel on these dates. The above said is applicable both for Russian business and tourist visas
The Russian Consulate will only issue you a visa if all the documents they require are completed correctly and submitted together. They never provide any help in acquiring any documents you may need, or in completing the application form itself.