Can I assign a special role to some students on a specific course resource?

Yes, it is possible. For example, the teacher can decide to assign a Teacher role to his/her students on a specific folder in order to allow them to quickly upload some files. To do this, you have to click on Assign Roles, the last icon on besides the resource. If you want to assign the Teacher role, click on Teacher, then select the names of the students you want to assign the role to, and move them from Potential Users to Existing Users.
Attention: if you assign the Teacher role to students, you allow them not only to upload files, but also to delete them from that specific resource!

(last update: 28.06.2018)