Here are the sample links to the ones you marked ????
C0: https://item.szlcsc.com/99021.html
C1: https://item.szlcsc.com/73589.html
PINHD-2×4: https://item.szlcsc.com/59402.html
I recently asked the factory to send me the BOM for OS 3.2 master, AC driver, DC driver boards, and I’ve attached them here. I will upload these to the Github repository shortly. They have reference links but they are all from Chinese websites. Most of them are from http://www.szlcsc.com, which fortunately has a English-facing site (lcsc.com). If you look at the item on the Chinese site just copy the item number and go to lcsc.com to search for the same item you will find pricing in US dollars. I believe lcsc ships worldwide. Some other items have reference links on taobao (basically the Chinese ebay). You can find those on aliexpress.com, which also ships worldwide.