Feeling like a POS just for thinking it....

We adopted a 2yr old cat in May and it's been going downhill. We've been implementing behavioral training (since adoption) recommended by the shelter and her vet, but if it doesn't start to show improvement she's going to have to find somewhere else. Our neighbors have complained because she will howl for hours after we leave and you can literally hear her in the parking lot coming up to the complex. She howls while we're home too even if she's been fed, been tired out playing, or during getting attention. We've brought her to the doctor and no health issues. Just recently she's started waking our son up at night on purpose to try to get food. She figured out if she bangs on his baby gate it wakes either us, or him up, waking us up, and thinks its chow time. You can't lock her in a room because she'll claw the door to shreds (we tried caps she chews them off) and screams non-stop. We're going to have a newborn in April and I can't deal with it all and a baby. I vowed to never be one of those people that return a cat to that horrid place but my next option is fostering her until they can find a better suited home....