Some people handle carbs better than others, but 50 grams per day is pretty low, pretty much almost a ketogenic diet depending on the rest of the macros. That is fine and will work, but it may or may not be necessary to go to such an extreme...but again, this will vary person to person.
In my opinion, a lot of the bloating that goes on with most of us can come from any food that continues to digest slowly while exiting through the GI tract. For example, many proteins (especially low grade and cheap protein sources) can cause bloating and gas because the longer they travel in the GI tract before getting absorbed, the longer the bacteria in the large intestines/colons etc have time to feed on them and release gases of their own. Same with high fiber foods like vegetables, beans, some fruits, whole grains, etc. A lot of people run off thinking they have some kind of GI disorder, when all they have to do is buy better quality protein sources, cut back on the overall amounts of certain foods, or even add more water to their shakes to help with solubility. That doesn't make these foods bad, it just means that if you have a lot of broccoli or beans or protein for the day, you will probably get gassy and bloated to some degree.
Yea, it's hard to say how things will happen with each person who has their gallbladders removed. Some are fine and others can have issues with certain foods, or rather the amounts of certain foods. Most people though tend to look back afterward and say they feel much better after it is removed (after dealing with a non-optimal output/functioning GB).