#...perhaps?

Wait did I forget a question

I think they would take on similar roles as Ingo and Emmet! Emmy would likely take on the single train and Ingrid would probably prefer the double train, but they don't mind switching it up and trading from time to time. They're naturals at battling though, they've got that strength in their genes. The only thing that may differ between them and their predecessors is their personalities.

For Ingrid, she is already super spunky as a child and I don't think that would change into adulthood. Every time someone comes into her train car, she gets so pumped. She would probably hop up and down excitedly before realizing it's time to get serious and starting the battle.

Emmy was quite shy as a kid, but as an adult she outgrows it a bit and just becomes more of a reserved and quiet person. When people step into her train car, they may get intimidated by her serious expression before she speaks to them in a gentle and encouraging voice.

Just like their uncles, Ingrid and Emmy treat the trains and the whole station with the utmost respect. They don't tolerate bad behavior and enforce safety rules strictly. Visitors really like them and trust them just as much as they trust Ingo and Emmet (who would also still continue to run other trains and join the girls on multis often). The depot agents love how the Battle Subway has become a family-owned business of sorts and seeing the Subway Bosses all together is very wholesome.

And just as a fun added bonus, here's some dialogue I made if you were to challenge these girls on the subway:

Ingrid: Thank you for riding the Battle Subway today! To get this far, you must be strong. Very, verrrry strong. Oh! I forgot to introduce myself. I'm a Subway Boss. Call me Ingrid! Now, exactly what kind of Pokémon do you have? How in sync are you? Will this battle be your final stop? Only one way to find out! All aboard!

My heart