"...I see. This girl loves me."
Bro, she just confessed to you not long ago. I understand he has trust issues from Hanabi's constant gaslighting, but the way he put himself on the line for her sake during the false accusations arc would have you think he already trusted and liked Fumi enough to do all that for her sake. Will he really go above and beyond to help a girl he doesn't trust?
That said, I will not take away the cute fact that this will be the first (real) date for both of them. Please let them fumble and succeed their way together through this, have them learn the ropes of romance at the same pace. It's actually good they talked it over for like two hours, proper communication in a relationship is always a good thing.
If Hanabi does not appear again at any point after that rebuke I'd be very surprised. I'm still expecting her to continue harassing him because it would be out of character for her to just give up and never come back. Someone as proud and arrogant as she is typically don't give up so quickly especially when they feel they have a score to settle.