Elimination diet and she is still having issues
I don't know your back story, but I have heard from at least one mother who had the experience where she felt like her child had allergies, so she started on the elimination diet, and things got worse rather than better in terms of blood in the stool. It's possible that this is what happens when you first start, and things will get better as you keep on and the gut heals itself. It's also possible that avocado & bananas could be the problem. Some people are allergic to bananas, avocados and kiwis, and are also allergic to latex. And then if you have a pollen allergy, you can get oral allergy syndrome that is a cross-reaction with the pollen that are found in certain fruits. Zucchini is related to a ragweed allergy, I think. So it's possible that you haven't gotten all the reactive foods out of your diet.
There are other causes of blood in the stool. Kelllymom has an article about it: http://kellymom.com/health/baby-health/bloodystool/
Only you can say whether it is worth it to try elecare, but if I really thought food allergies were the most likely culprit, I might feel it was worth trying while maintaining my supply, and see if it made a difference.