As long as a rose is grafted into Fortuniana or Dr. Huey rootstock, I would not worry (I would lean towards Fortuniana stock personally). Those two rootstocks are resistant to root knot nematodes, Fortuniana more. But Carpet Roses are typically own root, that is, not grafted; same for Easy Elegance Roses. Once in Florida, see if nurseries carry them in grafted form. Typically though, they are not grafted. Of course, if you are going to grow them in containers not in contact with the soil then you could grow them in containers.
http://homeguides.sfgate.com/carpet-ros ... 96510.html See "Winter Hardiness" "One thing that makes Flower Carpet roses rise above winter-finicky roses is their roots. Rather than being grafted onto the roots of another rose, Carpet roses grow from cuttings that develop their own roots."
Spring has sprung, so let’s talk about roses. More precisely let's talk about roses that you can grow. We have all heard the comments, "I love roses, but they always die,” or “roses take too much of my time and energy." With the Easy Elegance® rose collection, we can now put this aside and treat roses like any other shrub. Since they are grown on their own root , they perform better, are hardy, and don't require heavy chemical sprays or intricate winter protection. Unlike other roses that are budded on a different variety’s root system, even if Easy Elegance roses die back to the ground after a tough winter, they will grow back the same rose you purchased. If you plant a budded rose and it dies back to the ground, you end up with a completely different variety in your garden!"
Most own root roses will not adapt well to areas with nematodes.