I am sorry to hear you are worried about Charlie, and that she has so many problems. My name is Rebecca. I am a veterinarian and will do my best to help.
The frequent heat cycles are very worrying, as is the heart murmur and the pulmonary hypertension. These polyps are impressive in appearance as well; how long have they been there?
If she has heart disease and pulmonary hypertension I would be very reluctant to do anesthesia. Have the polyps been tested? I might start with doing FNA, fine needle aspiration to get cells from inside these polyps for microscopic examination. If they appear benign on FNA, and if she can urinate normally, I am not sure I would do surgery. If the FNA reveals cancer cells, then I would consult an oncologist before considering surgery.
Anesthesia, with heart disease and especially pulmonary hypertension, is risky. If she were mine and I was determined to spay her and to try to remove the polyps, I would only do it if a board certified veterinary anesthesiologist did the anesthesia.
I have never seen polyps like this myself. If this were my own dog or my patient, I would start with FNA to find out what these are.
Let me know what other questions you have, and if this is helpful.