Hello,
Was this estate where you found the hats located in San Francisco? Without seeing any photos of the labels, it would seem that your hats are all from California, more specifically the San Francisco area. I would be more sure once I see the labels themselves. Maison Mendesolle was an exclusive and expensive shop located in the Saint Francis hotel in San Fran. Yvonne is another San Fran label, and may be a brand name used by a larger hat making company (not sure on this). Coret was a hat firm in San Fran too. And of course Joseph Magnin we know as what was once a high end department store in the same area.
If we see more pix, we might be able to get a better idea of the date on each hat, and what each is made of.
The Joseph Magnin and the Mendesolle would be the "better" of the hats. The other labels are more mid range hats.