Between those beauties, I'd go with either the Kona Dew Plus or the Trek 7.2FX

I would add the Woman's Raleigh Classic Roadster to that line-up, as well!

Though I'm not impressed with the front derailleurs on either, I'd tend to lean towards the rapid fire shifters on the Kona as opposed to the speed shifters on the Trek.

However, you know interceptor is right. Finding your nieces proper fit, is a priority to finding the most appropriate bicycle. Besides, she should be allowed to ride it and get the feel of it, after she is properly fitted. Take her around to a few of the local bike shops, so that she can see for herself.

I'll bet she'll even love you more just for that experience alone!

- Slim