I had a satin who died of complications from osteodystrophy. I'd stay away for that reason, although otherwise I'd be all over that piggy.
I do, however, fail to see how this ad "sounds like a breeder" and think it's fairly silly and sad that folks here sometimes look so desperately to find something like that. If it were a breeder, what would she care if males live with females? If anything I'd think she'd not be suggesting he only live with other males, that's for sure. It's also comical to think it's a breeder because you've got a "history of breeder searching to find the little details." That's fairly comical, actually. That aside, a person having 7 guinea pigs isn't an indication of anything - many folks here have that or more, or near that amount. I did at one point.
I think it's a little sad and a disservice to pigs looking for homes to be so desperate to see them as "breeders" because you think you have an eye for it. Breeders that advertise on CL usually say so loud and proud and don't give away animals for free and suggesting they live in same-sex pairs.