I would advise a Google search for pendant drum shade chandelier drum shade hanging drum shade and then look at "Images" as opposed to "Everything". Can try it with "Shopping" too. You'll see a number of fixtures that closely resemble the one you like. Didn't see the exact one, but there may be something there that you can work with. Good luck!!

No idea, but I would ask $40 for it. I have nice antique pieces I can barely give away right now. The manufacturer name isn't going to fetch a higher price.

Yes you can retrofit, if you have clearance. I installed a pot light near the edge of the house (hip roof) and it came close to not fitting. I agree with ICAT cans. Otherwise you would have to get in the attic and spray foam around the entire can to make it air tight (leave electric box accessible). Having air tight pot lights in an unconditioned attic is very important. Not important if the pot lights are between floors in the conditioned space.

I haven’t been able to find the exact light, but here is the design firm that did this room: https://lucyinteriordesign.com/portfolio-urban_romantic.htm Rejuvenation has a large selection of tube sconces: https://www.rejuvenation.com/catalog/categories/bath/all-bathroom-lighting?page=7 Home Depot has a similar one, too: Tube sconces This bathroom was done a few years ago, so it may be that this particular light isn’t sold anymore. Such a beautiful room!