How would getting a health insurance benefit for my U.S. citizen child impact my EB-5 I-829 process?

You are a conditional U.S. permanent resident now. Obtaining Medicaid health insurance for your U.S. citizen daughter should not affect your pending I-829 petitions. However, you should present this question to your immigration attorney who filed your I-829 petitions.

First, you are a lawful permanent resident and therefore are not subject to a public charge inadmissibility determination. As a permanent resident applying to remove conditions, you are not required to establish that you are admissible to the United States. Also, even if there was current or past receipt of public cash assistance for income maintenance and long-term institutionalization at government expense, this is only one factor to consider in the totality of the circumstances; other factors include the statutory minimum factors (age; health; family status; assets, resources, financial status; and education and skills). It does not appear that you have a problem.

I would call a health insurance broker and discuss options. Is your daughter eligible for Covered California?

Simply purchase insurance for your daughter. No one can force you to accept public assistance for health insurance.