I just returned from WDW, and I saw Snow White three different days in front of the Big Hat at Disney-MGM Studios. She was there usually around noon to 3:00, on half-hour intervals. Twice she was there with her Prince! She is not there every day, but pretty often.

Also, we saw the Queen there too!
I also saw Snow White in a spot I never seen her before in Magic Kingdom - it was behind a store in Liberty Square, on the side facing the main walkway into Adventureland (sorry hard to describe!). I also seen her on other trips in the old Skyway Landing near the Peter Pan ride, heading from Fantasyland into Liberty Square.
One time I saw her in Germany at Epcot, but not recently.
As for dwarves, Dopey is fairly easy to find. We seen him at Town Square in Magic Kingdom (where you first enter), also by the Big Hat at Disney-MGM Studios. The other six dwarves are very, very rare! We only seen them at special events, like Mickey's Halloween Party.
Hope you find Snow White, she is my favorite princess!
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