Hi, I'm new to this forum, so this is going to be my first forum post.
As for questions 3 and 4, remember that could very well be Buster's imagination, since he is narrating. It may not be reality.
But here are some other possible answers.
As for why the tigers are solid orange, that's probably because adding white to them may have made coloration and animation more complicated. But, like I said, it could very well be just Buster's imagination.
Also I looked at a map of areas inhabited by Siberian Tigers, and the highlighted area showed was quite close to Manchuria/Northern China. That could be why there are Chinese characters on the box.