DS160 form questions

Hi guys,
I am on H1-B and planning to go back to China for a short visit soon, and is working on the new DS160 form and have couple of questions - hope you can help.

1. does any one know where I can find the "passport book number" it asks? or it doesn't apply to China passport?

2. I visited US couple of times before, and the form asked for last visit, what is the "visa number"? I looked at my US visa stamp before, and saw on the lower right there is this 8 digits number in red, is this "Visa Number"?

3. I am traveling with my daughter, one of the question asks "relationship with person", should i pick "parent" or "child" ?

4.for the home address, home phone/work phone etc, I should NOT use my US home address and phone #, instead I should some address in China even thought I haven't lived there for more than 10 years, is this correct? I guess at least the mailing address should be in China.

5. for last 5 US visits, it not only asks for Date of Arrival, but also asks for Length of Stay, wonder how you guys fill in the length of stay? It has dropdown lists with years/months/weeks/days, since I am on H1-B(before that was F1), how am i supposed to calculate the length? Just do the math on, say, the duration from my previous entry into US to the day when I left for China? which maybe say 3 years 2 months and 11 days, how do you guys put this down? in total days? in weeks?

6. have you made specific travel plans
I have booked the round trip for my upcoming visit to China, so I have the arrival date for US for coming back, but it also asks for departure date in the form, I am on H1-B, and I am in the process of getting my green card and my I140 has been approved, I can just renew every 3 years. In this case, what departure date I should put down? The best i can think of is the date when my current H1-B renewal will expire. Is that how you guys do?

Your quick response is greatly appreciated and thanks for the attention to my questions.