Some notes:
* Change Arecus's plates around a lot. I posted a set with Sky Plate but get ready to use some other plates like Zap (Electric), Fist (Fighting), Flame (Fire), etc. You may also change the coverage move (Flamethrower) just in case before some battles, but keep Calm Mind, Judgment, and Recover.
* Kyurem-W's Choice Scarf may be vital for revenge kills and whatnot, but Icium Z is really necessary for it in Big Mo and Tessy.
* The Hoenn legendaries are necessary to disrupt the special weather against Mirskle (Fog), Alice (tailwind + Delta Stream), and Tessy (heavy rain). Mega Rayquaza can hold very item and there is no mega stone for it; it can mega evolve as long as it knows Dragon Ascent.
* Necrozma-DM is a key member since its Prism Armor allows it to lower the damage from super-effective attacks. With Weakness Policy and Dragon Dance it can become the ultimate killing machine.
* Note also that Mirskle and Galavan battles are double, so watch out for them too.
* To get Necrozma-DM you may need N-Solarizer, and Marshadow will hold it if you redeem its code in the postgame. After getting it, fuse your Necrozma and Solgaleo using this item to form Necrozma-DM.
* To get Kyurem-W, you need DNA Splicers, and Genesect will hold it if you redeem its code in the postgame. After getting it, fuse your Kyurem and Reshiram using this item to form Kyurem-W.
* Finally, note also that some of the mons may be inaccurate (I may run Surf in Kyogre just to not mess with the inaccurate Origin Pulse, for instance). I have not played Unbound for around seven months, so I wrote some of the moves from memory.