When gallbladder is removed, the bile is constantly flowing from the liver into the intestine, so fat malabsorption does not result from gb removal.
I've mentioned fat malabsorption because you've mentioned "oily" stools. Fat makes stool whitish, floating, foamy, sticky and foul smelling. If stools don't float it's not likely fat malabsorption. Maybe it's mucus that gives oily appearance. Mucus is translucent, not bright white as fat.
Pains may be from gas built in the part of the colon where it runs below the ribs. In this case, pain would be maybe relieved with having a bowel movement. Anyway, this may be considered as IBS and low-fodmap (low-sugar) diet might help you in this case.
http://www.medhelp.org/user_journals/show/118248?personal_page_id=801
To say if they are fats and no mucus, you'd need stool test for fats.
Weight loss and mucus in stool also appear in intestinal parasites. Stool test for ova and parasites can reveal them.
If cramps resemble those from the gallbladder then they may arise from blocked bile duct. MRCP or ERCP is for diagnosis.