What would you do if Poochyena was real
>>56968325Might not be the exact answer you're looking for and more obtuse than a direct method, but I used Dolphin emulator + VBA link to get Celebi and Jirachi on my livedex run because I didn't have a proper GBA-GC Link Cable working, but did have a DS Flashcart to dump my Gen 3 saves.
Your situation's a bit different, but there is a Wii homebrew application that allows you to dump GBA saves with the link cable, so if you use that, you should be able to get your save up on emulator and then get Jirachi/Celebi that way.
https://github.com/FIX94/gba-link-cable-dumper/releases 