Yes, you can use third party EAN to list new products if they had not yet listed with those EAN numbers. if you want to list Wholesale products with their codes you can do that or better to have cheap EAN number from https://codesforamazon.com/product-category/barcodes/ean-numbers/
it will make more control to your listings and easy to sell at amazon with your own brand name as well. also you can have exemption if that will have an approval from amazon which is some time taking.
CategoryEAN UPC ISBN BARCODES