I came across this thread and started wondering how reliable the wikipedia page is. The article has something old-timey to it, and my experience with other viking related wikipedia sites makes me very suspicious towards this particular article.
In my limited experience, I can answer at least some of the first part of your question. The Rus' formed many kingdoms, of which the most influential were based in Kiev and Novgorod, essentially founding the basis of Russia. They were the main force in the region and really served to unite the region as a whole under one main culture and force. When the Mongols invaded, the Rus' continued on the Eastern Orthodox tradition they had adopted and kept their kingdoms interconnected. Alexander Nevsky, the famous Russian war hero, was a Rus' leader who was "commanded" the city of Novgorod. I say "commanded" because of the complex politics involved with the Novgorod city leaders and the Rus' kingdom in Kiev, in which Nevsky was ousted several times but always brought back in in times of peril. Nevsky successfully defeated the Catholic church's incursions into Eastern Orthodox tradition, and defeated in several battles Scandinavian and Catholic crusaders around Novgorod and the Baltic States, near Riga. Nevsky and the Rus' preserved the Easternness and the Russianness of Russia at the time through to the era of the Moscovian tsardom.
It is also interesting to note that the Eastern Orthodox church language, Church Slavonic, was very similar to Old Russian, and they played a very large part in developing the Russian culture that we know today.
Edit: Church Slavonic