Some questions on the DOMA federalism theory

I’m also one of those who are skeptical of the federalism brief against DOMA. But I have a few questions, based on perusing the recent posts here and elsewhere by Dale, Randy, Jonathan, Nick, and my former boss Ed. (I read the brief itself a while back, but declined to sign; forgive me if the answers to my questions are right there in the brief.)

1. Ed distinguishes three types of statutory schemes: (a) a statute attaching consequences to marriage, with a definitional section defining “marriage”, (b) a statute where the word “marriage” is simply replaced with its definition, and (c) a statute without a definition of marriage, but where “marriage” is defined in a separate statute. Would the federalism theory be fine with (b) but not with (a) and (c)? Or, based on the idea that Congress has no power to care about what’s a good marriage, would the theory would also invalidate (b)? What’s the dealio?

2. If the problem is that Congress enacted DOMA for the purpose of furthering traditional marriage, does that mean I have to buy into purposivism or intentionalism to buy this theory?

3. What about all the statutes granting benefits to a spouse derivatively of the eligibility of a primary person, like Social Security (for purposes of survivorship), the immigration laws, etc.? The statute could have been written to apply to the actual eligible person: no Social Security benefits for widows, no special immigration treatment for the wife of an eligible person, etc. And yet they did write the statute to give special treatment to spouses that isn’t available for boyfriends/girlfriends, business partners, best friends, chess partners, etc. What was Congress’s power to do so, thus privileging the marital relationship over other kinds of relationships (even long-standing non-marital romantic relationships)? Does Congress have a legitimate interest there?