It sounds close to the Stall ability, though I don't think Stall makes it move after end of turn effects activate. Using Stall as a base to start with would help visualize your new ability.
I don't think it works on Linux. Though I don't use that, so I don't really know. I use Windows. And yeah, I know it's laggy. The lag issues weren't fixed until later versions of Essentials.
Great script! I think I ran into a problem, however. It seems that if the Pokédex has more than one regional dex, this seems to mess with it and causes the game to not recognize them. Maybe I did something wrong though, on my side, it's possible. Just thought I'd bring this up anyway!
I've noticed a lot of people skip her dialogue. First I'd advise not to! My games are story-heavy. You're supposed to inspect the wooden sign to the north of Mondelo Beach. I'm going to add this to the guide, too.
Cobalion is at Ryoku Gardens, the very top right above the waterfall.
Dratini is found by fishing at any pond in the Nature Preserve. Thanks for playing, also!