Completed this commission three times. Mona did pay her rent. There is no achievement associated with this commission. Mona does give you her special dish, based on Satisfying Salad, quantity is one. Makes sense, I doubt Mona can afford to give much food away.

Finished today, upon completion, Mona also gave some of her specialty food.(Can't confirm if it was 1 or 2 she gave).

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I finished the commission today with meeting up with Mona, there is not hidden achievement for this..

library done

you're missing Childe in the list.. His story quest was my absolute favorite of them all i really wanted to play it twice so i would exit the game a couple times so that i could go back and go through the part i was on from thr start again