I see Eder and Pallegina in my collection under "All" but just with a ? on the card, no details. Does that mean I have them but they are undiscovered? I'm a total newb
I don't see the Goblin Golem of Obsidian anywhere.
You are not a 'total newb'. Usually, the unlocked cards are shown in full and only the locked cards have name and a huge ?. You can see these cards as an option All/Owned/Treasure in the Collection, so you know of their existence but not what they do and so on. However, there are some promo-type cards in the Rise of the Goblins adventure path that are marked identically ('?') even though you have them unlocked. Grindylow and Birdcruncher Crown, for example. This looks as the same big inconsistency. You have the card but unless you encounter them during play, you know nothing about these allies - how to get them (checks), abilities, traits.
And there is something even worse - cards you can encounter in the Fighter's Tale adventure (another DLC) are not even shown in the Collection :-D
Regarding the Goblin Golem of Obsidian - have you looked in the Rise of the Goblins set? You can change it by arrows around the Rise of the Runelords logo in the Collection