I see this as Mitsuki trying to be the bigger person by going “I know the two of you are not talking because of grudges so I want to create an opportunity for you to make amends since this is an issue that can be resolved by talking”.
The slightly self-deprecating part of giving the tickets SHE won and SHE was looking forward to as much as Aya might be seen as bad, but as we were previously informed, she goes to shows a lot, and her Uncle might even be able to fix her up with other tickets (he knows venue owners and other people in the business or just die hard fans of western music). She might have questioned if she actually needs it if it means her friend Aya will not be entirely happy unless she solves this issue with Chizuru.
Mao is chill. Mao might be the one to approach Aya actually, but then hopefully it will be “too late” and Koga’s plan already worked —in one way or another — and Chizuru will be the one to talk.
If Aya comes out with the truth and ends up telling her friend that her crush turned out to be Koga, still apologising but explaining that it isn’t a matter of friend x friend, instead love interest x friends (which doesn’t excuse her behaviour of leaving her pals hangin’), it could be progress and we might get wingwomen for Aya.
If not the ChizuMao duo, Mao is my bet for the one working with Naruto-kun to nudge the gays.