Hello Hoshi. Welcome to the forum. (I know, I'm a little late.) Not a lot of people keep Indian Stars over here. At least not in comparison to some other species. I don't have any stars, but I'll share some general tortoise info with you.
Part of the reason for the less than tremendous number of responses to your questions is that you have moved into the realm of opinion. Different people do it different ways and all of them might have great success with THEIR method. Often how one keeps them needs to be dependent upon the environment you live in. I live in a desert area, so I have to go way overboard trying to maintain humidity, hydration and moisture for my species. Other members live in warm swampy areas and they have to make sure things don't get too wet and moldy. None of us really know what your climate is like in your part of India (although, I'd love to go there someday). So just make your best guess and adjust according to your tortoises.
As far as what happens in nature regarding hydration; I don't let that influence me too much. Dozens or hundreds of babies die in nature for every ONE that makes it to adulthood. That ratio is unacceptable to me. I can't afford dozens of torts to try get one to survive. So I do the things that I know will help give them their best chance at survival in captivity in my enclosures. As I said, I don't keep stars, but I do soak all of my young ones of all of my species everyday. I also spray their shells several times a day and provide humid hide boxes too. And all of mine are "desert" species. I have never heard that excess soaking will cause any nutrient deficiencies, but that does not mean Samstar is wrong. It could very well mean that I am ignorant and he is right. I can tell you that I have been doing it this way for three years now and have not had anything but success and healthy tortoises with it. To date, I have raised 42 hatchlings of three different species this way, and they are all growing smooth and healthy.
Part of the reason for the less than tremendous number of responses to your questions is that you have moved into the realm of opinion. Different people do it different ways and all of them might have great success with THEIR method. Often how one keeps them needs to be dependent upon the environment you live in. I live in a desert area, so I have to go way overboard trying to maintain humidity, hydration and moisture for my species. Other members live in warm swampy areas and they have to make sure things don't get too wet and moldy. None of us really know what your climate is like in your part of India (although, I'd love to go there someday). So just make your best guess and adjust according to your tortoises.
As far as what happens in nature regarding hydration; I don't let that influence me too much. Dozens or hundreds of babies die in nature for every ONE that makes it to adulthood. That ratio is unacceptable to me. I can't afford dozens of torts to try get one to survive. So I do the things that I know will help give them their best chance at survival in captivity in my enclosures. As I said, I don't keep stars, but I do soak all of my young ones of all of my species everyday. I also spray their shells several times a day and provide humid hide boxes too. And all of mine are "desert" species. I have never heard that excess soaking will cause any nutrient deficiencies, but that does not mean Samstar is wrong. It could very well mean that I am ignorant and he is right. I can tell you that I have been doing it this way for three years now and have not had anything but success and healthy tortoises with it. To date, I have raised 42 hatchlings of three different species this way, and they are all growing smooth and healthy.