All of the symptoms you describe sound very much like plain old IBS. A lot of people have gas problems, along with a feeling of incomplete evacuation, stomach rumblings and almost every one of us is worse in the morning than at night, regardless of C, D or A. As far as I know, none of your symptoms has a name, other than to be known as a symptom of IBS.
I can tell you that when I tried taking fiber pills for constipation a couple of years ago (I was on a low-fat diet and those can cause constipation), they made me WORSE constipated. Don't ask me why fiber made me more constipated rather than less, but it did. When I tried the same pills back this summer to see if they would bulk me up since I was having D, they made the D and the gas pain much, much worse. I won't touch a "fake" fiber anything anymore. If it doesn't come from actual food, I won't take it. The weird thing is those fiber pills only had like a gram or two of fiber in each of them, so it's not like I was ODing on them or anything. I mean I got more fiber from one slice of bread than those things, yet the bread never bothered me.
Fiber can cause bad gas cramps in people who are not used to taking it, espcially if you don't start with a very small dose and work your way up. There are several people on here who have had bad gas reactions to fiber supplements. You may want to try an anti-gas pill like Beano or something similar to help with your gas problems and cut the fiber out all together to see if it is contributing to your problems. The other thing I would suggest if your colonoscopy comes back clear (probably will) is to get tested for food allergies. Gluten (wheat) intolerance or out-and-out allergy messes up people's intestinal tract quite a bit. I think that it is usually accompanied by D, but everyone is different when it comes to IBS.
Have you tried Equalactin? It's never done a whole lot for me, but then I first tried it when I was actually having gall bladder problems, not IBS. It seemed to help me some when I took it this summer for really bad D. It may have made only a small dent in the D, but it did pretty much take care of my pain, so that was at least half the battle. It's a type of calcium that balances the water in your intestines. If you have too much, it absorbs some; if you have too little it helps keep the moisture in there. Don't ask me how it works for both D and C, but it is recommended for both. I know a lot of us have had good success with regular calcium supplements, but normal calcium supplements can constipate. This is a different form of calcium that equals out the water balance in the intestines. Unfortunately at $3-$4 for a box of 24, it's much more expensive than regular calcium, but if it helps you, you may find it's worth the price. You can get it OTC in the U.S. It's in a red and white box and Walgreen's in particular stocks it with the other bowel medicines (like immodium).