This thread is resolved. Here is a description of the problem and solution.
Problem: I am trying to import products translations with REST API, I only have one language active
Solution: Please follow this documentation for how to create products: https://wpml.org/documentation/related-projects/woocommerce-multilingual/using-wordpress-rest-api-woocommerce-multilingual/
Also, I believe you will need the secondary language, otherwise the translated product will be created in the default language.
This is the technical support forum for WPML - the multilingual WordPress plugin.