Hi,
I have become interested in South African and Australian plants.
I have:
Dombeya Cacuminun
Barleria lupulina
Berzelia galpinii
Isopogon formosus
Passiflora tetandra
Telopea speciosissima

I haven't tried Leucodendron though. It is interesting how some of them are totally different species like Barleria lupulina, but resembles a Cassia. Dombeya Cacuminun grows similar to a royal poinciana, I don't know if these similarities to Florida plants would help them adapt.. I have researched this topic and gardeners in California seem to be successfully growing some of these plants. The Australian natives seem to prefer a warm Mediterranean climate, and overfertilizing and overwatering seem to do them in. I have just started my collection, but so far, so good with my plants. The data varies on the hardiness zones, I think since they haven't been introduced widely some nurseries estimate.

I highly doubt most plants in he protea family will survive here.