Can I make statements with structure like "我这个“老外”这么喜欢看京剧"?
You can. And people can understand what you me. When I read from left to right 我妹妹，一個漂亮的女孩 I can understand 一個漂亮的女孩 is used to describe 我妹妹 since the context and only ， between them.

I think if you want to make it more clear, you can use 是個 or 是一個 to substitute 一個 because it help to link them together. 是 is used to denote things that is other things. So A is B in traditional Chinese is A是B. So you use 是 or 是一個 can help to link 我妹妹 with 漂亮的女孩 and 他爸爸 with 一個老師 together.