Vinyasa basically means "breath synchronized movement" and has become a rather generic term used by yoga studios and gyms. It is often used interchangeably with "flow." It says very little abou whether the class is easy, intermediate or advanced, although I will say that vinyasa classes move fairly quickly as that is the point of the "flow." I don't know whether any of NIFS classes are geared for beginners; I would just make some inquiries. They share some instructors with my studio. Anha Hoke is particularly good. With your current injuries, I would be hestitant to recommend it until you are more fully healed and with the consent of your doctors.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher