I think since she will be the only NHR and the youngest you won't have a problem with her being super dominant.
One other thing I noticed with these birds is that they were the very first to start laying of my 4 breeds and they lay almost daily. They are very productive. Now a year and a few months later, their eggs are starting to be a little more oddly shaped with more calcium clusters on the outsides of the eggs. I don't know if this is true but it seems like since they started earlier and layed more eggs than the others their eggs are starting to show their age much more than my others. Although I do get more meat spots in my Buff Orpingtons eggs than in any of the other breeds and their eggs are still perfect looking on the outside.
I now also have black australorps and blue and lavender ameraucans in my flock in addition to the New Hampshire Reds, Speckled Sussex, Buff Orpingtons, Easter Eggers and Speckled Sussex/Easter Egger mixes and by far, hands down my favorite birds are the Easter Eggers. They are beautiful, sweet, not aggressive at all, hardy and independent. They do not lay as many eggs as the other breeds (They prob lay on average 4-5 eggs a week each) but to me the blue eggs are pretty hard to beat. They seem creamier somehow and the yolk to white ratio is perfect. I will never not have Easter Eggers in my flock and I'm considering over the next few years just having Easter Eggers and Buff Orpingtons. Thats just my two cents. :)