We had 6 for a couple times. 6 is too many for me but it was doable. The only issues were health (old dogs then Hiro's problems) and then Ada being totally untrained.
One thing I will comment on is the 'it's okay if you don't have high energy dogs'. Paps can have quite a lot of energy so I wouldn't assume this dog will necessarily be a 'chill' dog. But not all are like that. You could have 6 Roses very very easily without doing much at all. Having 6 Mias would drive even me batshit crazy. I've joked about buying Mia's brother when he was for sale. My entire family's response was a flat 'NO! Are you crazy!?'