You read my mind, I've been pondering this same issue. So on the bright side, we get two questions since one of my riddles stumped the koi. Since Lily hasn't been here long and thus isn't aware of the specific details of everything beyond Karsa's intro and the little bits she's managed to pick up from people she would probably stick to what's striking her as most important about the information she does have, something like:

Where in the east do we have to go to get home?

For the same reason, how often do you best a magic carp and get the chance! I really like both of your questions, though Lily doesn't know enough about The Merchant to really advocate for that option if asked.

On a semi-related note, I'm not sorry that she's going to try and high-five him when they beat the carp.