After numerous attempts and failures, I finally managed to get my own shiny Uxie! It really proved to be a tricky one with all the NPCs running around in the city. I actually had to hit my timer0 and frame 3 times because I managed to knock it out with a critical hit twice.. Talk about bad luck, especially with such an annoying catch.
I also noticed something weird while RNG'ing the Uxie. I used two different seeds, first one with a shiny on frame 437 but wanted one with less frame advances so I found another one which had a shiny on frame 201. I managed to get the first shiny before changing to the other seed, doing nothing out of ordinary and simply stopping the frame advances 1 before my target frame. On the second seed though, when I did this I never got a shiny when I did exactly the same thing. Propably the NPCs advancing the frame between closing the menu and talking to Uxie. So I tried again, still stopping 1 frame before my target and again, no shiny. 3rd and 4th times I tried stopping one or two frames earlier but still had no luck. Finally I gave up and went back to using the first seed, and voila, got a shiny Uxie (which I then also knocked out) very soon by once again by stopping one frame before the target frame. Third time's the charm though, finally caught the shiny pixie after a long fight.
All of this made me think that the NPCs might not be all that random. They acted very consistently on the first seed, always advancing the starting frame by 31 and never after the advances, and also on the second one since they always advanced the starting frame by 30 and always after the advances as well. Or, maybe I was just lucky. Knowing this might help someone else in the future though so I thought I'd write it down.
Uxie *, Modest, Luxury Ball
31/21/31/31/31/31
lv 65, UT
I also noticed something weird while RNG'ing the Uxie. I used two different seeds, first one with a shiny on frame 437 but wanted one with less frame advances so I found another one which had a shiny on frame 201. I managed to get the first shiny before changing to the other seed, doing nothing out of ordinary and simply stopping the frame advances 1 before my target frame. On the second seed though, when I did this I never got a shiny when I did exactly the same thing. Propably the NPCs advancing the frame between closing the menu and talking to Uxie. So I tried again, still stopping 1 frame before my target and again, no shiny. 3rd and 4th times I tried stopping one or two frames earlier but still had no luck. Finally I gave up and went back to using the first seed, and voila, got a shiny Uxie (which I then also knocked out) very soon by once again by stopping one frame before the target frame. Third time's the charm though, finally caught the shiny pixie after a long fight.
All of this made me think that the NPCs might not be all that random. They acted very consistently on the first seed, always advancing the starting frame by 31 and never after the advances, and also on the second one since they always advanced the starting frame by 30 and always after the advances as well. Or, maybe I was just lucky. Knowing this might help someone else in the future though so I thought I'd write it down.
Uxie *, Modest, Luxury Ball
31/21/31/31/31/31
lv 65, UT