I think it's really critical you check into the specific school's guidelines.
For example, regarding the spousal income issue, at Lewis & Clark, in their program information, not only is spouse's income included (regardless of filing status) but so are domestic partners:
For LRAP income eligibility, a domestic partner’s income will be treated exactly the same as that of a married spouse. The term “partner” means spouse or domestic partner. A domestic partnership is defined as a partnership with all the following characteristics:
1. Two persons living together in an exclusive and committed relationship; 2. Who are financially interdependent; 3. Who are not related by blood or adoption; 4. Who are both at least 18 years of age and mentally competent, and;
5. Who are not legally married to anyone.
So don't just assume it won't matter. It might, depending on the program. Obviously, domestic partners aren't filing joint taxes, so filing status isn't necessarily the deciding factor, check your school's program carefully.
Also, according to their program married/living with a partner recipients income is calculated by either your income OR half the total combined joint income, whichever is HIGHER.
So, my boyfriend and I (who are domestic partners, I'm even on his health insurance as such) if my income is 40,000, so I'm under the cap, and his is 80,000, they would calculate MY income for LRAP purposes as 60,000.