Loot items lifetime, capacity, availability

Hey, LoLers, so I am kind of hoarding all my chest loots that I have unlocked especially the skin because I am unsure of which one I want. Let me get to the point: Is there some sort of capacity restriction for the loot inventory? Do the skin shards unlocked remain in the inventory forever? And finally, I have not received any orange essence in a very long time, I'm talking months, anybody knows a reason for this? Thanks, ^^