I am from Manila and currently in the US as a consultant for a US company, going to Shenzhen for Business, can I request a multiple entry business visa?

Hi,
I am from Manila and currently in the US as a consultant for a US company. This US company has a Shenzhen office and I am scheduled for 2 months visit. During my stay, I am planning to visit my family in the Philippines one of the weekends. My questions are :
1. Would it be possible to request a multiple entry visa here in the US for the China visit? I have never been to China.
2. If I won't be given a multiple entry visa, can I apply an entry visa at the airport with a duration of more than a month upon my return from the Philippines? If not, what are my options. Please note that I will only be away for the weekend.
3. I have been trying to find an airline from Shenzhen to Manila but I can only find Hongkong - Manila. Is there any airline you can suggest?

Thanks a lot in advance and more power!