Thank you for getting back to me! Really appreciated!
Yeah, the rescue thing was a little vague on my part. Sorry for that!
Last year, I was able to assign legit methods, IVs, and similar values to various Hall of Fame Pokémon. However, this Ho-Oh is a rather unique case.
I did try to adjust Ho-Oh by changing its IVs, but PKHeX does not accept any variant.
These are all the variants that I was able to recreate. The file includes Method 1, Method 2, Method 4, Channel Method 1, Channel Method 2, and two different alternatives that I got thanks to the IV⇆PID Calculator.
10ANIV Ho-Oh.bin