This turned out well, but with a bit of a twist.
Remington has basically known only the rescue center from which he was adopted. He had his kennel, the cat area, a small yard in which he did his business, and a short half-mile walk. That's what he's known for the past three years.
Okay, now insert him in a situation where there are four loose dogs around him. He reacted with faux aggression. Snarling, showing of teeth, and even a faux fight that my dog, Maya, didn't recognize as faux. After the dogs were separated, Remington went to a crate in a spare bedroom to calm down. Maya was unhurt and Remington suffered no damage either.
That faux aggression continued (with no further fights, faux or otherwise) until Peggy and Remington left this morning.
Very puzzling - Remington has never shown aggression to any other animal, but apparently defended himself with distinction against the rescue center's bully, a boxer mix named Gidget, a couple years ago.
We believe that Remington will be fine in a setting that he can get accustomed to. Peggy has a cat, but Remington has never had problems with cats.
The whole thing is based on contingencies -- if it doesn't work out, Peggy can bring Remington back. She's interested in working with him, so we have high hopes things will turn out fine once he is acclimated to his new surroundings.