Becky, sounds like you have a lot of fun plants! I am very fond of Epiphyllums too, like many of us around here.
Now to overwinter them around here - I find the species ( oxypetalum, phyllanthus, strictum, pumilum and more ) are not too happy with chilly temperatures, I bring them inside with my Orchids.
But the hybrids, especially those with some red in their blooms, don't mind temperatures in the 40 F at all. Many people in Germany would store them years ago in their coal cellars over the Winter and let them go pretty much dormant. I do something similar, I keep them in the frost free garage over the Winter, temperatures go down into the forties and when they come through the Winter, they really bloom better than keeping them warm year around.
Now back to Orchids, some repeat bloomers-
Lc Mini Purple 'Blue'
C. Sacramento Rose
Bc Binosa 'Tetraploid' has a bunch of spikes in the works
And here is a final picture of the huge Ornithophora radicans.