Olga's website is comprehensive and helpful. Sometimes we just get used to talk like that. The existence of "了" normally means the past tense.

I think the biggest problem is that, sometimes you cant find a similar pronunciation in English, or there are some slight differences between the pronunciation you think and the true pronunciation. I meet the same problem when learning English. 1. you should strengthen your Chinese soundmarks, the pronunciation is combined by those soundmarks. Especially pay attention to, "sh",'ch','c',"s","en","eng"....It is not easy to introduce the differences with characters. 2. Watching CCTV news is a nice way of learning the pronunciation. The comperes are the tops among China and they wont add dialects in their Chinese. 3. Accent is a problem too, I have heard many foreigners talking Chinese, the accents are strange, so you should concentrate on the tone of the sentences. They are quite different from English. Wish these will help you.

My YouDao dictionary gives "n. 有钱人；花花公子；爱打扮的人". but maybe "高帅富",'富二代', is more accurate and suitable.

Most time, when you meet an elder, "您好" is unavoidable. Then you can choose "先生", "女士" depending on the gender. We usually ask a stranger's last name with sentences like this "请问先生您贵姓" to shorter the distance. If we know his/her last name, then we can use "张先生",“王女士” instead of "先生" to show the respect. Normally, "你好" is ok, and "hey, 哥们（兄弟）" "帅哥" “美女” are commonly used among young people. If you cant judge how to choose a title when opening a conversation, you can just say "你好（您好），。。。" and begin your topic.

I dont know the level of your Chinese, so I choose to answer your questions in English. 1. As I have known, a Japanese passport can visit China(include Hong Kong and Macau) without visa. You can stay in China mainland for 15 days. If you wanna stay longer, you can go to Hong Kong and come back, then you have another 15 days. 2. Bus isn't a wise choice when travelling in China because of the long time and uncomfortableness. 3. If you choose T-train(特快), it will take you about 19 hours and ￥200-600(depend on the seat or bed you choose) to Shenzhen. If you choose G-train(高铁), you should change the train in Wuhan, it approximately takes you 10 hours from Shanghai to Shenzhen with about ￥600. Then you can go to Hong Kong from Shenzhen(it is convenient and fast). 4. Even train is a better choice than bus, I recommend you to travel via airplane. It is cheap and fast, the management is OK too. 5. I dont know Macau's situation. Hong Kong is safe at night. And there are thousands of tourists from mainland enjoy the vesperal scenery there. From my perspective, the security is not a problem in Hong Kong and Macau, but the money is.