Hardware Sonic Adventure 2 Chao Region Issue

[Nickel1817]

So I’m trying to get a Tails Chao (along with Knuckles and Amy) and I’m using a GCN Japanese demo disk iso on nintendont to access the chao, which you can download through the SADX demo. When I try transporting the chao from the Japanese Tiny Chao Garden to a Japanese iso if Sonic Adventure 2, the game acts like there is nothing there, even though they are the same region!
Note: The chao are not saved on a copy of Sonic Advance 1, 2, or Pinball Party. It is on a download garden.

 

[Nickel1817]

Here are some pictures to show my scenario.

 

[SuperrSonic]

That's very strange, you could try https://gbatemp.net/threads/region-patch-the-sonic-dx-chao-distribution-disc.508216/
I sent an Amy Chao via third party cable to NTSC-U SADX and from there to a US Sonic Advance cart.

If the TCG in your GBA doesn't show the 'transporter' upon connection then it's likely that the iso isn't actually Japanese. You really just need to change a byte to get it to work with other regions, I'd give that a try and see if it works. Though I used Devolution for transferring, Nintendont at least displayed the Chao + rings, unlike your last picture.