We went there for Breakfast 3 times during our trip last October. From memory we never saw both Chip & Dale at the same time. It was one or the other.
On one morning, I think it was a Friday, neither were there, but I asked the CM that seemed to be managing the Characters and explained that my son will be disappointed if he didn't see at least one of them. He then arranged for Chip to come out about 15 min later.
We did see both Chip & Dale together and got a great photo at Goofy's Kitchen. They were out the front in the photo area, when we were waiting for our table.
Cheers
Angela