Many Paradise Pier rides (including Mickey's Fun Wheel) close before World of Color, so if anyone wants to ride any of those rides at/near nighttime, you may need to watch your timing. I understand that TSMM, Ariel's Undersea Adventure, and Goofy's Sky School are still open during World of Color, though.
In my very limited experience, the non-thrill-rides that are still open seem to get shorter lines during World of Color, though that could partly be people going home as the day winds down. (And if you can stay until park close, then lucky for you, locals who have work on Monday may be leaving before then on Sunday.

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I wouldn't count on the lines going down for RSR during WoC. But it worked out for me at TSMM several years ago, though, getting in line maybe 10? minutes before the park closed; the line was fairly short. I
think you can hear World of Color from part of Toy Story Midway Mania's queue so that would be kind of neat. (If I recall correctly, I happened to get off the ride in time to see most of the show from the wrong side.)
Around the time of World of Color on a Spring Break Saturday in 2012, Mater's Junkyard Jamboree was practically a walk-on. (And I could see a few of
Disneyland's fireworks from the ride too!)
I personally would NOT make it a priority to do Mater's Junkyard Jamboree early in the day (and probably not Luigi's Flying Tires either). At least in the past, those lines started out long in the morning from Early Entries and actually got a bit shorter in the afternoon and evening too. If you like Mater and/or his kind of music, you may get a kick out of his queue too...I find a 15-minute wait enjoyable. So I would not be too scared of a wait there.
Have a great trip!