If I were to buy a gig of someone reading lines, would I be able to monetize the video since I purchased it from them? Or is it a seller to seller thing for this?
Unless the Seller specifies otherwise, you own whatever you buy on Fiverr.
I do voice over from your script or text. You own the recording. I narrate videos and I’m sure many of them are being “monetized”.
If you buy a gig of someone reading your script on camera (video) you own the video (unless the Seller specifically states otherwise).