If you know CSS and are used to theme.scss then you should be able to do the tasks yourself? You can add the code at the bottom without caring if the above file is minified or not. If you have an updated theme your theme will have theme.css instead of theme.scss
4: Currently Shopify wants to update everything about css to make the site work better, so Express theme has updated to minify css. If you want to add css, just go to theme.min.css and paste the code at the bottom of the file, you can enter to make it more visible. Ex: