Yeah, it is difficult to get rid of noise on skin tones without making it look plasticky. I think you could leave the noise in the first two images as it doesn't really detract from the overall image and works well in an urban style and it gives it some depth.
As an aside I tried some noise reduction on the first, which got rid of the noise, but I actually think the version with noise works better. I just did it on the background, not the subject:
You can see the diff here on this part of the background:
Before: After:




