I agree with answering their questions with other questions. I also agree with using the scriptures against them. I would also suggesting having them answer YOUR questions. Some questions I would suggest is, 'Is the purpose of your visit to draw a line in the sand where you would say, 'on this side you're with us and on that side you are against us?'"
"Do you look at a man's spirituality as being so black and white?"
"Do you think that the only things that make up a persons belief system is belief in the GB and belief that this is the only truth and nothing else?"
"Are you here because I have been asking questions about my faith?" If they say yes then remind them of the scripture about how, after an assembly all of those in attendance went to the scrolls to see if these things they were told were true. I can't remember which scripture it was but you can find it easily. Use this against them and prove to them that you are following scripture. And that, if they wanted to help you follow the Bible ways then they would assist you in finding the answers.
If they ask you if you believe in the GB and that this is the truth ask them, "One can't have a strong faith without knowlege of what it is he believes in. I believe the bible does say that a house built on the sand will never stand. Only a house that has a strong foundation will. Well brothers, that foundation is knowlege and the only way to seek knowlege is to ask questions. Since this is scripturally correct to do I am curious as to why you feel threatened by it. If there is nothing to hide why do you have a problem with me doing what people in the bible are noted as doing? Is there something that you don't want me to find out?"
Then point out that their own literature points out that you are not to rely on your own understandings. That you need to rely on what THEY tell you. Ask them, "Well, since you say for me not to rely on my own understandings but to rely on the F&DS and the GB and the elders, why do you then refuse to answer my questions? If I can't rely on you to answer these questions then I have no one else to rely on but myself. Who'se fault is that? You could end this now by answering my questions. Why drag this on any longer than it needs to? Shall we end this now with you answering my questions?"
If they refuse put the blame on them for the reason that you can't answer THEIR questions. "So let me get this straight. You refuse to answer my questions but you want me to answer your questions. Do I understand you correctly? In order for one to answer a question, doesn't one need ANSWERS? Since you know the very fact that I have questions and you willfully refuse to answer them how can I answer YOUR question? You make it difficult for me to do the right thing. I would LIKE to believe this but I find it difficult to believe anything when one refuses to give me the truth to these matters. Nothing would please me more than to have the answers to your questions. Help me help you, brothers. Help me answer you by answering me. Can't you see that I am in need of spiritual guidance? Why do you refuse to guide me? You are supposed to be the sheppards here. Why are you neglecting the flock in this way? " (Play it up. Start pleading with them. Work up tears if your able to. Act like you are REALLY confused and conflicted. But at the same time DONT answer YES/NO to their questions until they satisfy YOUR questions.
These people are like the Gestapo and they only see things in black and white. They want you to have unshakable faith but they don't want to back that faith up with scriptural proof. So until they can answer the questions that you have in order to validate your faith then tell them that, by their own inactions and the shirking of their spiritual GOD GIVEN duties, THEY are making it impossible for you to accurately answer THEIR questions. And then tell them that you would be more than happy to answer them once they have made it possible for you to do so.