I was wondering if you could answer a question for me. The drag and drop functionality is working as it should unless I specify a default type for a Library. If I do so, I receive the following error when trying to upload:
Error: Insert failed. First exception on row 0; first error: FIELD_INTEGRITY_EXCEPTION, Content of this type cannot be published into the library as it uses restricted content types.: 
A) Default the content type of the upload app to the same type or:
B) Have the content uploaded from your app convert to the relevant content type of the library?
Any help would be appreciated.
It looks like just a permission issue at your end. Your user who is trying to upload the content doesn't have the permission.
Yes, you can set the default content type from native content type. Drag and Drop are not converting the content to the relevant content type of the library. We are only allowing the user to select the library and that content will be published into that library.
Hope that helps.