I'm starting to get a sneaking suspicion that the Shadow Missions aren't tied to quest grades. It appears that once a Taillteann/Tara shadow mission is selected, the quest picks from the pool of available shadow missions. More testing is needed, but if that's the case then these pages can possibly be simplified with a link to the shadow mission category in the future. Until then, I'll continue adding the quests as I get them.
In the long run I was expecting to go through and clean it up so that the Objective Info would just list all possible shadow/theatre missions similar to how pet expedition does rewards, but I wasn't absolutely sure that all missions would appear for all levels. Mostly because the Briefing is almost exactly the same for all of those similar missions.