たち for most of the time gets translated to "We" or "us" but in this context, Momiji-tachi would just be Aya and Momiji and since Momiji actually says "aya-sama" i say the translation has no need for it and is fine as is.
Meow!Woof!It is a walk, right Ran-shama!That's right. It is a walk.It's not that. Aya-sama and Momijis are drivers!We're drivers, right? Ran-shama!Oh, good afternoonChen and co. are on a walk too, right?Is it fun in the car, Chen?Woof!Meow!Cool ThingsAre you going on a walk too?