There are many types of condenser mic, but having looked at what is supplied with the Focusrite package, I'm assuming that it's a large-diaphragm mic. Ideally, a shock mount would be better; its purpose is to reduce ground vibration through the mic stand from being picked up. If you're not recording over a tube station, and don't jump up and down whilst singing, it shouldn't make too much difference.
A pop shield has two main uses: firstly, to prevent the singer from approaching too close to the mic (some singers 'eat' the mic; not good..!), and also to reduce spray from landing on the mic; the capsule inside won't like that, and is not so easy to replace as a dynamic mic. Without such a device, it can be made fairly easily by bending a wire coat-hanger into a circle, and covering this with a ladies stocking or similar. As long as air can pass through, but not spray, it's good enough until a better-quality filter can be acquired.
Be aware, of course, that the condenser mic will require the phantom '48v' to be turned on, as they need power to work. Turn this off again when reverting to the dynamic mic.
Hope this helps; good luck with the project.