Bringing in over $5000 USD

Two of us are traveling to China for an adoption. We are going to do some sightseeing first. We are flying from USA to Beijing for a few days, then to Hong Kong for a few days, and then taking the train to Guangzhou for the adoption.

We need to bring $9,000 USD for the adoption itself and we have 20,000 CNY and 12,000 HKD for spending money (3 weeks).

Our purpose for carrying this cash is for an adoption. We can provide proof of the adoption as well as proof of our plans for sightseeing. Can we anticipate any problems, or duty tax? I realize we are crossing the border 3 times and that makes things more complicated.

Thanks in advanced.