Allow remove item from cart but not edit quantity?

Hello,

I see 2 solutions for you :
1. Easy and quick => Use some Css to don't display quantity and relative elements with this kind of css command :

.checkout_html_class .quantity_input_class,
    .checkout_html_class .quantity_input_plus_class, 
    .checkout_html_class .quantity_input_minus_class {
        display: none;
}

Hello

Advice for create a good priority css command :
1. Check that your selector is well written, good class html and no mistake or typo
2. If your command is visible in your inspector tool, but is overrided (css command crossed out), then his priority isn't strong enough.

=> Some css priority system explanation :
From less to the highest priority :
.html_class_element {command: value}
.html_class_module .html_class_element {command: value}
.html_class_page .html_class_module .html_class_element {command: value}
.html_class_page .html_class_module .html_class_element {command: value !important;}

Note, that if 2 css command have strictly the same selector, then the last written in the css file will be the one used.

For override view, you can use with your display view file, the navigator inspector tool, for this you can point your quantity input, then right-click => Inspect (inspector tool etc...).
you will see a new window that will show you html elements and more especially this will help you to find this elements in your view file.
Then you can use comments in order to "shut down" this required part.

Hope this will help you to achieved what you need.
Regards