a) All IFC group facilities are rented or owned by the chapter using them (I believe only two fraternities actually own their houses, not sure on sororities);
b) IFC groups do not receive student activity fees and, I don't believe they are subsidized in any other way by the university -- there may be certain things that happen between landlord and tenant for those groups that rent, but that is not university subsidy as we are discussing it.
c) Fraternities and sororities are recognized by the University though. Under IFC their charters are recognized. The University further has the power to regulate and even throw greek houses off campus. Those determinations are made through the IFC.
Fraternities and Sororities are probably more akin to a club athletic team (except a different funding structure) than an SGA group. And, fwiw, I would bet there is some form of anti-discrimination policy in place for fraternal organizations -- just not covering gender or requiring being open to all students. Those rules would be established by the IFC and not under the SGA umbrella though.