Bile acids/salts can be measured in the blood but these tests do not provide much useful information. Therefore, these tests are not commonly performed.
2. The important thing is to find out whether you have stones in the bile duct. If you do indeed have stones, these should be removed either by endoscopy or surgery.
3. There is no harm in removing the gallbladder. In fact, a diseased gallbladder should be removed without delay otherwise it can lead to more complications.