I do see a slight problem here.
-“Tell me about it,” Harry said and Snape frowned. What? Hadn’t those Muggles worshipped Potter enough for his liking?- This takes place after Snape's Worst Memory. So Snape has already seen memories from Harry's mind showing a bit of the abuse he suffered. So he should at least not be surprised anymore. He would still be surprised when he learns the level of abuse and neglect Harry suffered, but the fact that Harry doesn't like living with them shouldn't have even got a raised eyebrow out of Snape.
And another thing that occurred to me just now. Hagrid told Dumbledore he got the bike form Sirius Black. Dumbledore 'knew' that Sirius was the Secret Keeper and had obviously betrayed them. Yet he didn't even bat an eye at Hagrid's mention of him. This would almost seem to support theories that Dumbledore already knew, would explain how he so readily believed in Sirius being innocent when they told him. It would make great fodder for a Dumbledore conspiracy story. I can't believe I only just now noticed that.
You're right about Snape, but at the same time, we don't know exactly what memories Snape saw each time, so for the purpose of the story, I'm going to go with the bit that he's still somewhat in demial...it seems like a Snape thing to do I guess.
As for Dumbledore, nice catch! You're right, it does sound weird...and would make for a great story!