Marvelous story! Geek!Albus is terribly cute, going off into magical architecture. I'm not surprised Viktor was charmed. Scorpius is a believable, likable problem roommate who might grow up some day. Viktor is just overall great. He and Albus should have fun redoing the pub. :-)
I loved this bit:
"You will," Scorpius insisted. "Because under that good-hearted and bookwormish exterior, you are a cold-blooded Slytherin who will get what he wants no matter whose feelings get hurt."
It was several hours later, and halfway to the pub that Albus realised that had been Scorpius's way of calling him a romantic.
*giggle*
And I love Harry's "I'm sure I'll be very proud of you when I figure out exactly what you've done." :-)