Unless her friend's in-laws are the pregnant ones, I don't think that their approval or disapproval should be a factor in whether or not you have a shower for your friend. A baby shower is a time to pamper the new mother to be and wish her well on a very happy occasion. It is held before the baby is born primarily because most new mothers are too tired after the birth of the baby to deal with a large number of guests. It is not about "collecting" gifts, although keep in mind that gift giving is a sunnah.
On a side note, if we are doing away with Hindu traditions then doesn't the entire rishta process and most rasams associated with it need to be scrapped?