I have two Collections in my Top Level Collection. Both have Card Images applied, though when I preview, I don't see the Collection Card Images, only the associated collections within those two in the Browse Pages. Shouldn't I see 2 Cards when the App initially launches? One for each collection in my Top-Collection?
There is no browse page for the top-level collection so you'll never see any cards for items in it. The top-level collection defines the set of items that make up the top level menu and left/right swipe accessible content when the app first launches.
To get the structure you're after you should make another collection (I typically call it "home"), and put that collection in your TLC. Then add your two other items to Home.