This is a fun little setting, and I do appreciate the couple of ways this incorporates Shadowdark's mechanics (mainly the Flickari being able to provide light once per day). Unfortunately, it feels like a setting made for its own purpose rather than something intended to be played with Shadowdark.
This is very inspired and well thought out as a setting, but for Shadowdark, it does not pull me in. IMO, this should be expanded upon as a system neutral setting, or expanded upon more deeply with a specific system in mind. As an initial rough draft though, there is a very fun idea here, and I hope you make more iterations of it.