Well, the Index will already radiate magic, but it's quite unlikely that a spellbook would ever be found in its inventory.
That being said, I really like the item, and might use it in some things I run. It's a really fun, flavorful item that definitely has some utility, and I could see, on a character or two I've made in the past, picking up one or more.
Same with the Animated clothing. At the point you'd be able to afford the clothing, you'd also be able to afford other versions of carrying capacity stretching, and this one is much more flavorful than a simple bag of holding, at least, in my opinion.
I wish I could comment on pricing, or balance, or any of that, but it's almost 6AM and I'm running on little sleep regardless. If nothing else, these are really cool items that I'm definitely going to steal.
PS: The Cantrip Pearls look fine to me, too. It's not particularly powerful, but there are definitely times when I've wanted another cantrip or two.