I have a couple of questions regarding the Wiki Page ID. Does it always stay unique for the page, where the page itself is just a placeholder for any kind of information that might change over time? 

Consider the following cases:

1. The first time someone creates page "Moon" it is assigned ID=1. If at some point the page is renamed to "The_Moon", the ID=1 remains intact. Is this correct?

2. What if we have page "Moon" with ID=1. Someone creates a second-page "The_Moon" with ID=2. Is it possible that page "Moon" is transformed into a redirect? Then, "Moon" would be redirecting to page "The_Moon"?

3. Is it possible for page "Moon" to become a category "Category:Moon" with the same ID=1?

Thanks,

Gintas