If those murals still existed, and Disney hasn't uncovered them in the last 20 years, then someone needs to be fired. The flying Space Mountains were ridiculous.
I once heard a "rumor" online that Winnie the Pooh only takes up the space of one of the Country Bear Theaters, and that the second theater is still around backstage.
I've decided that 9 times out of 10, the idea that beloved pieces of Disneyland's past existing in the park after their closure is wishful thinking on the part of fans.
Of course, I'm no exception. I've lately been curious about how much space Star Tours takes up in that building vs ATIS, and whether there are boarded up rooms back there with remnants of the attraction that Disney didn't feel the need to remove. Which is foolish thinking on my part. But it's fun to imagine.