for sure, it could be a thread for each podcast, or just a constantly updating feed of all lightning podcast episodes (each as their own item) so that SN users can rank each episode in the same way they rank posts on the main board.

can definitely use the pub key to transfer funds to podcasters, and the same can be done for comments. fountain recently launched cross-app comments, so anyone can see/post comments on lightning podcasts from any app that supports the spec.