Home Study Help!

Hi!We passed all our checks and backgrounds and everything required for our home study. During this process my husband has an adult daughter from a previous marriage. He has not spoken to her in 3 years due to her mental health and other issues. His door is open but because he will not give into her demands and lifestyle, he had to set boundaries for her sake and his. The adoption agency stated it was not required by USCI to speak to her but then they recanted and now want to speak to her (but still admit it's not required). Way before this, we told them about the severe mental health issues on the mother’s side and how his daughter had a lying, pathological kind, Issue. Severe issue as in making false claims against anyone, including friends and strangers if she was upset. They never said anything but sprung it on us 20 minutes before finalization. We told them there's no way we can trust her to tell the truth since she was upset her father got divorced and remarried. Based on her patterns with others, we can't trust her. She lives hundreds of miles away. He remarried when she was in her 20s and didn't live at home. They've admitted its not required but is insisting they will now not approve us if they don't. His daughter and him had a fine relationship until he remarried when she was an adult. They no longer speak for now. She also prefers her mother’s alcoholic life, etc. We've told them our concerns and they keep ignoring us. We told them we are MORE than willing to provide more references, do any psych rivals, etc., anything to help lessen their worries, but we cannot afford for her to speak and tell lies, and us not given a chance to disprove it (if she tells the truth then we are good to go). We also asked them what is our recours should she tell lies but they won't an der. And they keep pushing their personal parenting feelings on us. We consulted many professionals and they said we would be idiots to let someone who has a pattern of extreme lying of the sort she has to speak with anyone, especially since it is not truly required. We are so distraught ad they are the only international agency for our country, the home study one we can easily switch. We also spoke to several other families that had adult children not inside the home that weren't spoken to. Does anyone have any advice?