I feel that if any one member of the Strawhats is most likely to be forcfully taken from his Nakama it is the little Doctor.
But I don't think he will be a hostage.
People rarely mention it but so far Chopper is the only one who has developed a way to enhance Devil Fruit powers.
In the hands of the the wrong people Chopper's Rumble Balls would be a major advantage.
If word got out about a Devil Fruit drug I think that Chopper would become very valuable to the Government.
Those of you that say the Governmant is doesn't need anymore power hasn't been paying attention to the current arc.
I beleive a plot about Chopper being taken and exploited by the Strawhats enimies is not only likely its inevetable.