Thanks for your post.
I'm afraid it's bad news for both questions.
1. There is no way to custom map differently named tables in SQL Compare. It's something we would like to add to the tool, but the problem is that it causes too many issues with dependencies. i.e. every reference to the custom mapped object would also have to be rewritten to the new name.
2. It's not possible to exclude specific columns as they're not treated as objects in their own right. When you compare a table, all columns will be considered.