Severus Snape loved Lily Evans with all his heart, but Lily Evans was just a normal 16 year old girl with normal, respectable 16 year old friends and a secret crush on a certain charming Quidditch player. Lily's POV of that last conversation by the Fat Lady.
Horace Slughorn was a genial sort of chap. He'd give a leg up to anyone, regardless of House. As long as there was something in it for him, of course. And as long it didn't require any actual, you know, work. Here's his thoughts on the 1971 Sorting.
They say that if you want something done right, you have to do it yourself. But of course the Headmaster never actually intended for Harry to learn Occlumency. As to what he did intend? Who knows? It's not like he would ever share his motivations...