Use FeedMe with a dynamic URL The list of entries I need to grab is available here:

http://arcresources.mediaroom.com/api/newsfeed_releases/list.php?format=json


Each individual entry is available at a unique URL, by adding an ID, like so:

http://arcresources.mediaroom.com/api/newsfeed_releases/get.php?format=json?id=n


Is there some way to get FeedMe to create entries for every ID from the list URL, using the get URL?
There's currently no way to achieve this with Feed Me. A single feed would represent a collection of items to be imported as elements/entries.

One method your could consider is setting up a feed for a single entry, then use the optional url parameter when calling it via the direct feed URL. This overrides the URL used in your feed settings with the one you provide.

This is described https://verbb.io/craft-plugins/feed-me/docs/feature-tour/trigger-import-via-cron