The WDW shirt was a nice touch, seeing how that opened in 1971, too.
As for the pencil lines, Milt Kahl had this to say:
Barrier: Your mentioning The Aristocats reminded me of the construction lines that are visible in the old lady and the lawyer in the opening scenes.
Kahl: When I've shown rough tests to people, they seem to have enjoyed them. I think that if the animation is good and the character's believable, I don't think there's anything wrong with the thing being frankly a drawing. I don't think [the construction lines] really bother anyone. It's like the flicker of Xerox: at least the flicker of Xerox is a three-dimensional flicker, a flicker in depth rather than a flicker from side to side. And that's what we used to get in inking, especially in the very slow-moving scenes. When you have something that's held, regardless of how slowly it moves into the hold, it'll freeze [in Xerox]; and what I've done, very much in the past, is to have two drawings, one a tracing of the other, and alternate them. It's not that there's anything wrong with the freeze, but the audience will become conscious of it.