1- I'd like to know how having the figma or sketch files would help. Would those files provide font-sizes or other values like margins or padding ? I have no experience using either of the software but would consider if it helps making determination more precise then using the provided preview images.
2- I considered using a HTMLFormElement for this component. Pretty sure in the past I used a hidden check box or radio group for something similar. After some consideration I used ul / li's instead, pretty simple without having to struggle with radio or checkbox styling. It's only one value gong to javascript anyway. Is there a preference or a standard in these situations ?