You asked about ideas for questions...
Questions that might get them thinking:
Example: Get out your Bible Story book. Look at the horrid picture of Pharoah's army and all his horses being drowned. Look at the "godly" people, the Israelites. Why are they smiling??? Why are they smiling and even laughing at this scene of destruction when the Bible clearly says "Jehovah himself takes no delight in the death of the wicked one?"
Who wrote this book of Bible Stories? Oh yes, men who don't even have children….(oops, sorry, not quite true. Only ONE man on the GB has a child!)
Other example: Is underlining a sentence in a magazine really something that God approves of? Is it really a sin or bad thing if we fail to do this? Did the early Christians have to do all this pre-studying and meeting attendance?
What was the main theme of the New Testament (sorry, "Greek Scriptures"). Did Jesus tell us about doctrines and so forth as the main focus of his teaching? What did Jesus really tell people to DO? (Answer: Love God and Love your Neighbor! That was it!! He then demonstrated ways for us to do this!)
You could ask what Jesus meant when he said to feed people, to give them food if they are hungry, clothes if they are unclothed, etc. (Witnesses will say this only applies in a *spiritual* sense!! Maybe go further on thoughts like that… like why did the early Christian congregations take up donations to help each other? Why did the disciples suppose Judas had gone out to give some money to the poor? Why did Paul say he was EAGER to help the poor, after he met with the older men in Jerusalem, and that was the MAIN thing those older men were concerned about -- see Galations! Paul said that the older men in Jerusalem were more concerned that he should be making some gift to the poor, a thing he was already EAGER to do!)
What is this all about, counting hours in field service? Did Paul count his hours? When the Bible says to be generous, ready to share, not even keep accounts of the rights and wrongs, why do we keep our field service time accurate to the now-15 minute?
There are so many little questions you could try to ask, carefully, and when it seems appropriate… direct attention to the BIBLE because it so often and frequently TOTALLY CONTRADICTS what the WTS says.
And please do read some off Steve Haasen's stuff! Very helpful. :)