A great many of us here in the north plant multiplier onions in the spring, but tend to try to get them out as soon as possible (and plant as shallow as possible). They are hardy enough to winter over in your country easily; so you might want to plant now anyway and just let the bed set to winter over for next spring/summer. Most suppliers do not warn about short day/long day for these although they normally supply them for planting in the fall. That is not an absolute necessity either. My family never did for the multipliers that we had as family heirlooms in Iowa.

In Louisiana multiplier onions are nearly all called shallots as opposed to the specific special names the French use; so there you would have to do some sorting but should have adapted varieties for your area, if you can sort them out. There are also Texas and New Mexico strains of a number of types of multipliers, survivors of the missions, such as I’itoi multiplier from the Pueblos. These little squirts have drawn raves from the desert SW to Minnesota, but although they multiply rapidly are not very big. As I understand it there are similar types across nearly all the areas where the Spanish monks set up missions, but you have to dig them out. Few nurseries actually stock many of them if any.

There used to be a website heirloomonions.com that had a nice selection, except too often out of stock on many things. But it is gone now.