Since the Binder config is programmatic, you could use a loop construct based on a directory listing of the contents of that folder and then dynamically do map(“foo”).to(“bar”).initArg() bit on each one. I’ve never done it and I’m not sure if it’s recommended, but it would work.
As far as the DI annotations not being inherited, I just so happen have a pull request for that committed to my ColdBox fork on Github that is currently waiting on Luis to review. That would allow you to put the annotations once in the base object. Maybe if Luis looks at my enhancement soon and it passes review, it will make it into 3.5.2. 
https://github.com/ColdBox/coldbox-platform/pull/89
Thanks!
~Brad