But predicting her demise is non-professional, a pure guess, and is most likely wrong.
Her early post-op pooping was no doubt due to pre-op eating. I think she should have access to any food that she will eat, including banana. But maybe she won't even eat that at this point.
Minor blood spotting after surgery is normal, if it stops on it's own in a few days.
In her searching for a way out, does she rub her snout raw?
Sick iguanas need specialized and very long-term care. The ones who make it have kind and patient owners.
At some point you may need to force-feed food to her. Just to give you some hope, there is a rational and effective way to do that. In the past I took in many unwanted iguanas, and most were in very bad shape. That's where I learned how to force water and food.
Some people say that if an iguana isn't eating, there's a physiological reason that must be corrected. Sometimes there is. But I've found out that often an ig will just stop eating and starve to death over some stress that happened. Most of the non-eating igs I got were severely stressed, dehydrated, and malnourished, over a period of half of their lives. To save these, we have to bridge the gap between abnormal feeding and resumption of normal eating.
Using a 3cc plastic syringe, draw in 3cc of water. Hold her against your chest or on the top of a table (tabletops are good because the can't get traction on them), with her snout positioned so you can most easily reach her head with your hands at about six inches below your chin. Never get a part of your finger between her jaws. Pinch her dewlap between thumb and forefinger, gently at first, then as strongly as necessary and make a steady, slow pull until her mouth opens. If she hasn't already learned how to resist this, her mouth will open fairly easily.
As soon as it opens even a little, put the tip of the syringe between her jaws, and slowly push one cc of the water into her mouth. She may not realize what is happening, and let her mouth fill up with water and overflow. That is a good result for the first try. Push a little water in, and wait to see if she swallows. If she doesn't, push in a little more. If after some point she hasn't swallowed, move her head so it points downward and let the water drain out. Repeat these steps later. I've had igs learn to anticipate this feeding, and swallow eagerly. But it takes time and almost infinite care and precision so it does not scare them to death every time. But even if she struggles the whole time, this is worth it. Another way to open an igs mouth is to press a popsicle stick sideways between her lips on the side of her jaw. Most igs will try to reject the pressure by pushing on it with their tongues or biting the object. That gives you a quick chance to insert the syringe and push a couple of cc's.
Forcing food. Lay out a few ounces of a mixture of good food on a cutting board. Mince it finely into 1/8" X 1/8" pieces. You only need two or so tablespoons of it. This is much better than liquefied food, which I've tried. Cut the end of a 3cc syringe off, leaving it looking like a cannon barrel. Sand it smooth. Push the food tightly into the syringe. You can pack it all the way to the front and it will stay in. Open her mouth, put the whole end of the barrel between her jaws, and swiftly push out 1/3 of the load. Lay the food as far to the back of her tongue as you can. Withdraw and let her deal with it, then do it again. You must insist on doing this to her if she struggles against it, and she probably will at first. Use as much strength as you must to succeed. Your ig is much stronger that you may yet believe. But keep at it and she will learn, and will lose her panic response to this feeding. This is a life-saving duty.
But IMO, from what you said so far, it isn't time yet to start forcing.