More than one question 1.How do you get the arceas flute without ar?

4th question answer - You have to go back to Turnback Cave in the Spring Path by Route 217 and go to the end of the cave and there will be a portal. Click on it and it will take you to the Distortion World where if you go to the end of that (which takes like 2 minutes) you will find the orb to keep it iin origin form.

Shaymin and the Azure Flute were events, sorry. I have no idea how to get any of Deoxys' forms. To get into the Distortion World a second time, you have to get the National Pok�dex by meeting every Pok�mon in the Pok�dex and talking to Prof. Rowan. Then beat the Pok�mon League, even if you already did. Go to the Canalave Library and listen to what Lucian says there. Go read the book titled, "The Original Story". Then go to Celestic Town and go to the Elder and listen to the book she shows you. Then go in Celestic Ruins. Listen to Cynthia all the way through. Now go to the place you came out of Turnback Cave, and go back inside. Find three pillars and examine them from the front. Once you find the third pillar, go in any random room and Giratina will be there. Catch or defeat him. Then step in the portal and you will be back there. The item you can find there is the Griseous Orb. There is nothing to do there once you got the Griseous Orb. Hope this helps!