Puggle or Miniature Pinscher for 7 yr old boy with Cerebral Palsy?

Looking for a little playmate for my son and our eight month old male minpin (miniature pinscher). I'm thinking either a female minpin, or a female puggle. I don't know if keeping the breed the same would matter. The minpin we have now is sooo gentle and cute. He's curious, but doesn't chomp or pester the little guy as he sits in his wheelchair. They both play on the bed lovingly, and I'm told puggles are sweet natured as well. But I dont' know if it's better to accent one breed with another, or just stick with a female minpin. Any thoughts?