Spousal support is taxable income to you if it is by Court document - Order, divorce, separation. If it is not so documented, it is considered a gift.

It is a deduction for the person who pays it and income for the person who receives it.

Yes, you have to file tax returns.

Spousal Support - Tax Implications | LegalMatch Law Library (http://www.legalmatch.com/law-library/article/spousal-support---tax-implications.html)

The disability may or may not be taxable. It depends on whether you got it from your employer or the Social Security Administration or from a private policy.