Headscratchers / My Little Pony: Rainbow Roadtrip

• Why did Sunny Skies have to lie about the festival just to get the Mane Six (well, Rainbow Dash mostly) to come help? Couldn't he just write a letter saying "Dear Princess Twilight, please help me and the entirety of Hope hollow to bring the town it's color back. Also, send Rainbow Dash too. She is the best concerning rainbows."? Twilight is the Princess of Friendship and is not the type to turn a blind eye to the suffering of a whole town.
  • Best guess is that, since news of the Mane 6's exploits doesn't travel well (in fact Rainbow Dash seems to be the only one of the group that he immediately recognizes), he doesn't know going in that they'd be willing to just come help for the sake of it. Luring them in with promises from the Festival was a more sure-fire method of getting them to actually come to Hope Hollow.
• How are there colorful photos in the Rainbow Room, and only them? Were they developed later, or perhaps were in the red room at the time everything greyed out? Or am I thinking too literally and it's more metaphorical with the "even though we faded, the memory never did" that's kept them colorful? But if it was memory preserving them, wouldn't the whole room be colorful?