You should state where you are located as it is very difficult to get plant material of any kind into many countries without the appropriate paperwork. That includes seeds. From experience, the inspections required for the appropriate paperwork to export legally are expensive and a royal pain, which is why I won’t do it.
Beware of buying seeds of any kind through Ebay and the other online selling sites as they often are NOT what is advertised. I’ve known folks who purchased “rose seeds” and raised weeds from them.
Your best bet would be to ask for them on sites such as this or perhaps Garden Web/Houzz in the “Roses” or “Antique Roses” forums, Antique Roses Forum - GardenWeb , as long as you are located within the continental United States.
The main issue I foresee for you is there aren’t as many people growing the varieties you ask about as there was a decade ago. Add Si and Hi don’t set seed in my experience. They may form hips but they are most often empty.
A Premium membership to Help Me Find-Roses will help you greatly. It costs $24 a YEAR and opens all the search areas you need to research roses on the site. For example, searching sources for Perla de Alcanada, the gardens growing it which are listed, the first two are archives to show was USED to exist but is no longer. John Bagnasco’s Home Garden and Friends of Vintage Gardens list they grow it but they are associated with a rose society for auctions (in John’s case) and their own fund raising in Vintage’s case. Neither is likely to be able to assist in obtaining seeds from their collection. The final garden is the San Jose Heritage Rose Garden. Their interactive on line catalog shows they no longer have that rose. https://fm70.triple8.net/fmi/webd/HRGMaster
Unfortunately, none of the nurseries listed as selling the rose is in the United States so if you are, your best bet is to watch for the CCRS rose auctions (which is associated with the Bagnasco garden) https://www.ccrsauction.com/ and the Friends of Vintage https://thefriendsofvintageroses.org/ sales to see if they are ever listed as available from those sources. CCRS ships, Vintage does not. Looking up Montserrat, the availability is even more restricted. Faurax should be fairly easily obtainable (Burlington should have it) and a number of us grow it. Estrellita de Oro nearly doesn’t exist anywhere in comparison. Rouletii, Pompon de Paris and Oakington Ruby should be relatively easier to obtain.
Unfortunately, for rose availability, you are about forty years too late. Availability of odd, weird and wonderful things reached its last zenith in the US in the late eighties to nearly mid nineties. Then, there were MANY mom and pop mini nurseries around the country, offering all sorts of wonders. Miniature Plant Kingdom brought in material from all over the world, sometimes even legally! Sequoia Nursery offered a selection unlikely to ever be seen again here. Definitely search the lists from Burlington Roses, available by emailing BurlingtonRoses@aol.com and requesting her mini and large rose lists. Again, though, only if you’re in the US as I don’t believe she exports.
