If I create a child theme, will the changes that I currently have pasted in my themes "additional CSS" (not the actual style sheets) section remain?

Answer 1

Yes, they should remain even if you are not using a child theme because any CSS added into the customizer will automatically be added to the database. If you have added any code to your parent theme’s functions.php file, then it will disappear. Any CSS changes that you have added directly to your parent theme’s stylesheet (style.css) file will also be wiped off.