No, it's not taxable. You only have to pay if you worked for it. But in this case I'm not really that sure. That is why you should consult an accountant.
Yes, income from all sources is taxable by the federal government. This includes social security payments, pensions received, and even unemployment benefits.
As with many things related to the IRS, the answer is "It Depends." There are worksheets on the IRS website that can help you answer this question. Good Luck!
It's not directly taxable but they do find ways to get some of it back. Talk to your accountant about it and see if there isn't a way you can avoid it.