You can't amnesty Amare. It's amazing how many times the amnesty clause has been explained yet still is so widely misunderstood. RoyHobbs, probably face palms every time posts like this happen. He has explained it on multiple occasions in threads, the front page, etc.
The amnesty only applies to contracts on the team before the new cba was signed (aka the end of the 2011 lockout). No trading for guys and amnestying them, no signing guys and amnestying them. They (more specifically their contract) had to be on the team before 2011 season.
So basically the only players the Celtics are able to amnesty in all of existence are Bradley, Rondo, and Pierce. No one else qualifies for us not Bass, not KG, not Green. Also, the amnesty is a one time use thing so you can't use it multiple times.
With that in mind Amare's contract is an albatross/cap-killer. I don't think he improves this team enough to justify us taking on all that dead weight. Bass, Lee, Terry, etc are all very movable contracts in comparison. Preserving the cap is going to be very important in the coming years.
Sidenote: Feel free to let me have it where I was wrong.