Yes, I think you could safely grow Purple Rain in the birdbath. In your zone, just as in mine, the shade is bright shade and is a good place to grow roses. Some of my happiest roses get only a couple of hours of sun each day.
According to our database search engine, I have 101 Kordes roses. (Actually, I have more because I have duplicates of some of my favorites.) Most of my Kordes roses are fragrant, so I don't think that's anything new. If I have to pick favorites, I'd pick Aloha, Cafe, Caramel Fairy Tale, Die Welt, Fairest Cape, Gebrueder Grimm, Pompon Flower Circus, Pomponella, and South Africa. I can't narrow it down any more than that. Three of those are fairy tale roses, so that's clearly a series that meets my aesthetic requirements.
Cinco de Mayo is remarkably disease resistant in my garden, but probably because we have such low humidity here.
As for those awful nematodes, if I lived in Florida I would invest in roses grafted onto fortuniana rootstock. The nematodes don't go near fortuniana, so you can plant those roses in the ground and enjoy them forever. Many local nurseries in Florida carry fortuniana-grafted roses from Nelsons'. Here's a link to some retailers of Nelsons' Roses.
http://www.nelsonsfloridaroses...
Cool Roses in Florida also carries fortuniana-grafted roses, and I think they'll mail them to you.
http://www.coolroses.com/produ...
K&M is another mail-order nursery that offers roses grafted onto fortuniana. I've bought roses from them. They're huge and fabulous and worth every cent.
http://www.kandmroses.com/
I see Don Juan on their list under climbers:
http://www.kandmroses.com/K&M%...
