No you cant. And yes, this has been requested before. Probably the best solution would be the ability to set license per individual file.
Avast antivirus, its free, works well and it doesnt use much memory in my experience.
I think that annoying bug when cursor doesnt move position with keyboard arrows is back when you try to edit the post, you have to manually position the cursor with a mouse.
The good thing is withdrawals are once a month and even if the files were to be deleted they arent really deleted so they can be restored back. Still, maybe the password for deleting the files wouldnt hurt as well
Congrats on your sales!
I have something similar in my portfolio (jquery autoslide gallery).