Hello,
You can translate/rewrite all theme and plugin texts via PO file in WordPress. Here is a video tutorial that should help you translate your website texts with a Loco Translate plugin https://www.youtube.com/watch?v=D3NsDdMzsls&list=PLMw6W4rAaOgKKv0oexGHzpWBg1imvrval&index=3
Please check the video tutorial to see how to save the translation file correctly. You can remove the plugin and translations would remain. Also, translations would remain after each theme update.
As for the icon, please find the icon on this source https://fontawesome.com/icons?d=gallery or upload icon image into Media library and provide the link, I will provide custom CSS. Please advise if you want to change the Wishlist in the Header only or in the grid and on the product page.
Best Regards