Trust all is well at your end. I am so glad to hear that you are actively involved in engaging with our Hindu friends.
1. How can we explain that conversion is not evil or illegal as they presume? (Could you point to any resources that I should read/study?)
Answer: Well, first of all I would highly recommend that you read two of Vishal Mangalwadi’s books. One is on “India the grand experiment” and the other is on “Missionary Conspiracy”.
Anyway, if I were to respond to this question, I would begin by saying that no single worldview or religion is neutral or in other words all religion, if examined critically, you would notice that all do make exclusive claims. This includes even those who tries to accuse the Christian of ‘converting others’. So, in a sense, no religion is without any exclusive claims. Having said that I would also talk about ‘conversion’ in general terms (not only in the realm of religion alone) such as that we all do change our opinions (apart from religious commitment) on lets say politics or a product that we use or even academically! At least, the Indian constitution guarantees that we have those rights. Similarly, I would raised the question of why then is it wrong for anyone to make similar (free) choices in the area of religious commitment (provided it is not forced, as they seem to imply).
2. What are the highlights of missionary work in India that you would suggest to show that missionaries have added value to Indian society? (Is there a good source/books that talk extensively about missionary work in India?)
Answer: I would begin by arguing that according to the statistics (Government) the Christian population is said to be just about 2 to 3 % of the whole Indian population. When you look at the country as a whole you would notice two prominent contributions from the Christians both past and present. One is in the area of ‘health’ i.e., the Christian hospitals (E.g., The reputed Christian Medical College, Vellore) and others that are spread all over the Country including the rural areas. Second, is in the area of ‘education’. That would include both schools and colleges. Some of them ranks as one of the best in the country. In fact, some of the best leaders in the Country have graduated from these institutions. In terms of service, I would say that it is the 3% that has served the 97%. Therefore, we would do well in inviting our friends to imagine as to what would happen if the percentage of Christians were to increase from 3% to 10…20…50…80…etc.
Well, for more information you can also read the book, “The Christ of the Indian road” by E. Stanley Jones.