The reasons to prevent Google from indexing content are:
- The content should be private and not available through search engines
- Nobody would be searching for the information and thus wouldn't be of interest to search users
- The content is in a format that is not meant for human consumption
- The content is thin or low quality (if it isn't going to satisfy the searcher, such that they leave unhappy, it will ultimately reflect badly on your site as a whole)
It sounds like "orders", "messages", and "refunds" should be private. You also might not want "coupons" indexed.
"webhooks" shouldn't have human readable content, so you probably want to noindex those.
I'm not sure exactly how you use the other categories, but you could apply my rules above based on your usage.