What are the requirements for bring my kid to Beijing for vacation?

Your issue seems a little bit complicated. I think your kid can also apply for a dependant visa as a dependant to your present husband. However, your mother can only apply for a China tourist visa.

The documents for your mother are her passport with blank pages and at least 6 months validity left, a completely filled China visa application form V2011A affixed with one passport-size or 2x2
colored photo, with white background, full-face front view, and no hat, your invitation letter with a copy of your valid Chinese residence visa and passport information page, her previously used China visa in old or new passport.

The documents for your kid should include these:
1. His/her passport with blank pages and at least 6 months validity left before expiration.
2. A truly and completely filled application form affixed with one passport-size or 2x2
colored photo, with white background, full-face front view, and no hat. Application for an applicant under 18 years of age should be signed by one of his or her parents.
3. original NSO birth certificate and your marriage contract.
4. Copy of your husband's valid residence visa, working visa, working card and passport information page.
5. a Physical Examination Certificate for Foreign Citizen.
6. Invitation Letter by a Duly Authorized Unit or Confirmation Letter of Invitation issued by an authorized Chinese agency.

China Embassy in Philippines may require additional documents for the visa application.

I think the affidavit of consent from Phil embassy beijing notarized last march 2010 has expired, but you can confirm with the embassy again.