Tortimer boots everybody else out. There should be a "hierarchy" list of visitors in Liquefy's FAQ. Everybody in the higher tiers pre-empts everyone in the lower tiers. Running off of memory here, Katie/Kaitlyn is in Tier 4, and say, Katrina is in Tier 5. If you have Katie, you will not be able to get Katrina or anyone else in tiers 5-7. However, Crazy Redd and Lyle, who are above Katie, will be able to visit, and when they do, they take the visitor slot for that day and Katie is gone. On a day you don't have visitors again, Katie will return assuming she hasn't been in town a full week (when she disappears).
KK Slider is special in that he does not pre-empt anyone, and nobody pre-empts him. Every Saturday at 7:30 PM, he will be there come hell or high water.
Tortimer is Tier 1. He pre-empts everybody (except of course KK Slider.) So when you have a week-long event like the acorn festival, don't even bother looking for anyone else, they 100% won't be there.
My favourite math equation: i > u A haiku: Writing a poem / In seventeen syllables / Is very diffi