You're right! This would be fine for a beginner, although they are a bit long. I personally would start people off on a slightly smaller project to be safe, but that's up to you! I do recommend though that you don't do these until you have already done a sock in the same method, e.g. if they are top-down with a heel flap, make sure you have done one before.
Also do a long swatch and keep going until your tension has gotten quite good and even, and be scrupulously honest about gauge because colourwork is less stretchy than plain knitting.
And... check out Eunny's blog, a post called Tip, Tricks and Treats covering most of what you need to know about SC as a beginner.