Remaining Questions: Snape's Patronus

Well, I don't see much point in typing up chapter-by-chapter overviews or teasers, like I had started with chapter one....

I guess I want to pose questions I still have about the series.

This will still take several posts, and then I might abandon this blog. If I do that I will begin a new one that makes a fresh attempt to answer those very questions. In time, Jo might put much of our remaining doubts to rest. However, the blog will still be here, so that I (and others) could return to it at any time.

So, let's begin with Snape's patronus. I was under the impression (the first time we see the silver doe in the forest) that it was Snape's patronus, and that the doe represented Lily herself. Well I turned out to be correct about it being Snape's patronus. However, Harry tells Voldemort that Snape's patronus was the same as Lily's patronus. This means Lily's patronus was also a silver doe.

Two questions here:
1. How did Harry learn the form his mother's patronus takes? Where is that mentioned?
2. Previously in the series, Harry is told by an Order member (was it Albus or Remus?) that no two patronuses can be the same, so how could Snape have the same patronus? True, two does don't have to be identical does, and if they spoke they would have different voices, but still....