well, CATco is kinda gone in SR4.
however, i know i've seen at least a few people speculating on this, the seraphim were pretty danged crazy. iirc, most people assume that when ares absorbed CATco, they probably only got a few, if any, of the seraphim, and that the seraphim probably exist as a separate organisation dedicated to restoring CATco or something like that. do a search on them, you should find something.
perhaps one of the most interesting possibilities, imo, was that there would still be seraphim scattered all over the place in deep cover, some of them maybe not even knowing that they're seraphim until certain trigger phrases are spoken
but really, try the search