Lily is such a brave and funny little girl...and Luna being the elder and wiser of the two surely just thinks "Well, let her have her way..."

As soon as they have both settled in with the new situation you will know who's really the boss (I vote for Luna!)...

This reminds me so much of the introduction of my sister's younger cat Mulle to fourteen year old grumpy cat Moni...first thing Mulle did was walk straight to her litterbox and pee in front of Moni's eyes, while Moni (who always was a threat to all the neighborhood cats) looked just dumbfounded and then with a hiss and growl of disbelief...

They go along fine today...Mulle is still the funny baby who's allowed anything (she's three now), but Moni is the boss...