I have experienced a similar problem, in which the user was uploading documents of different types. I allowed the user some flexibility in how they accomplished the task.
- Allow the user to do a bulk upload to a specific type by having the various document types listed out. Each type is a row in a table, wide enough to be a reasonable drop target. So if the user has 3 floor plans, they can drag and drop them to a placeholder area called 'floor plans.' If you have a short number of types, you could list them all out in the table. If there are many, at least list the commonly used types out and have an add button to add a new type to create a new drop target.

- The other method is to allow the user to upload everything in bulk, and then list out all of the uploaded files and provide a dropdown to select the type for each one individually. You could include a multi-select option, where you could allow them to assign types in bulk if this is a common use case.
