As the statute vests the determination of status in the agency and such action is statutorily unreviewable, supporting criteria developed by the agency are also unreviewable, as they are merely interpretive aspects of the determination.
As the felony conviction of the alien's spouse and sponsor does not impede the marriage, but merely the right of the spouse to live in the US, the right to marry is not affected; further, the question of residency is much broader, and the limitation of the rights of the sponsor following a felony conviction is a reasonable one.
As the statute that attached new limitations to the rights of those already convicted was clearly intended to apply to past convictions and referenced post-enactment dangers, there is no violation of Ex Post Facto; waived anyway.
http://www2.ca3.uscourts.gov/opinarch/163440p.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.