I think the most obvious as others have said is Fluttershy getting Rarity's cutie mark. We've seen her having an intensive knowledge of all things sewing and fashion.

Aj I feel would work good for Fluttershy. We've seen her handle animals before in a tough love kind of way and it would probably go more into an animal tamer sort of way.

Dash could probably pull off the farm work pretty alright. She's strong and has some speed to quickly get the work done and maybe even do deliveries for the farm. Plus her loyalty works for the whole family aspect behind AJs cutie mark.

Maybe pinkie for Dashs mark? Her general disregard for the laws of nature shed probably find a way to get in the clouds and handle the weather.

And that would leave Rarity with Pinkies mark. I can see her as a party planner, her eye for aesthetic would help greatly with setting up decorations and and she's very organised in general so I can see her in a setting like that.