Hello, glad to see 1.2.0 made it!
Sadly however, I just spent over about an hour trying to get it to work, but every configuration across all versions of Dolphin I could think of turned the same result, crashing after choosing anything in the intro battle sim. I tried all your recommendations for Dolphin in the OP, and anything else I could think of, but nothing gets past that first selection for ol' Metagross (as well as changing Pokes or giving up).
Just wanted to give you a heads up, I'm sure you'd like your hard work to, well work after all! After I can get around to trying this again I'd love to leave some more in depth/constructive feedback for certain things about the hack since I haven't played since like 1.0 a couple years ago. There's also some things I'd like to open discussion about in regards to catch rates, boss fights with multiple shadow pokes, and other things related more to the core game, but for now I'd just like to try this version out and see what's new and fresh. Thanks!