Unfortunately, I don't have a Ho-oh with regenorator, and neither of mine are calm. However, I have a Ho-Oh that's level 50 that I caught in game in Omega Ruby (really stupid name. It's Rainbow with a bunch of symbols). I also have one I got from the GTS. It is shiny and it's level 100, most likely genned into the game. They both have pressure.
Would you be willing to trade one for Shiny Darkrai?
I have many other ledgendaries if you'd want at for it. I just really like Darkrai lol. I have a shiny Meloetta, although it's considered illegal XD
I also have a lot of Shinies if you are interested. One of my (legal) shiny ledgendaries is a shiny Rayquaza. It's ability is Air Lock, it's nature is Impish. A friend of mine got it x3
Anyways, it's alright if you don't want to trade for any of my Pokémon, but thanks for the chance anyways!