I deal with a lot of fabrics but not a lot of textiles so keep this in mind. There are significant labeling requirements normally with materials and country of origin, like you mentioned, but any supplier that has exported to your country should have standard labeling they’ll apply. If you get a dumbfounded response from a supplier just move on to the next. If you have a customs broker you work with, they’ll normally be happy to review a sample label for little or no charge. I’m also not sure any textile labeling is ever checked by customs at the time of import (aside from possibly children’s clothing) which takes away some of the stress.