Honestly, I hate to be the naysayer, but I would be wary of getting a 6lb dog to play with a 160lb dog. Even if Binn is super gentle, he is HUGE and the little guys are TINY. It just isn't a good combination unless you want to keep them separated when you can't supervise their play.
Pugs are, I'm sure, some of the toughest "little dogs" you can get. Dakota plays with a Pug here and the two of them have an absolute blast. Dakota tackles Otis and rolls him around on the ground and Otis just wags his curly little tail and snorts. If Dakota did that to some of the other small dogs out there, or to Ripley, the little guys would be squished.
Downside to a Pug is that you need a pretty heavy-duty purse and a strong shoulder to tote them around
Otis is solid muscle and he weighs over 20lbs.