Viking colonize America ??? Not true. They discover the American continent diriged by Olaf Ericsson by the end of 10th century, but that's all. They stay in North East Canada (Labrador and Newfounland) for 2 or 3 or 4 years and they quit forever after 2 or 3 or 4 very cold winter. They were unlucky.They did do good things. Like colonizing America and jumpstarting feudalism.
About feudalism, I not sure I understand what you want to said. However, it's sure they don't implement feudalism in North America.