The idea of optionally associating particular upload fields with the wordpress title, category or description might be a good one. I’m not sure how difficult it would be — I’ll put it on my list of things to think about when I have time.
I’m afraid I don’t know anything about the Media Library Categories plugin, though. There are so many different plugins around that I couldn’t think of writing custom interfaces for each one.
Plugin Contributor
teskeyn
(@teskeyn)
Taking a look round the web I found a post on github, https://gist.github.com/ahmadawais/0ccb8a32ea795ffac4adfae84797c19a about how to “Upload a file using the WordPress REST API” which seemed to imply that you could upload Title & Caption. Unfortunately I don’t know how you upload files in EntryWizard and whether this would be a possible solution.
As for the categories, I may forget about the Media Library Plugin and do it all with fieldsin Entry Wizard
The api you mention is used in entrywizard when you attach the image to a page.