Playlists based on remote items when they are big are really hard to handle. When you are trying to "resolve" all the episodes at once you end up downloading 100s of feeds and eventually get hit by HTTP 429 (too many requests). You can "resolve" the episodes dynamically when they are displayed, but this approach has it own limitations. I wonder if it would be better to also include some actual episode info in addition to the feedGuid/itemGuid?