Going to preface this by saying that I am by no means an expert at team building, but it is the aspect of competitive Pokemon that I enjoy the most. So here I present my attempt at Aurora Veils offense.
I felt the best play-style to maximize Aurora Veils potential is Hyper Offense, and thus split the roles into
Lead - Alolan Ninetales
Breaker 1 - Zygarde
Breaker 2 - Heracross-Mega
Sweeper- SG Magearna
Glue - Mew
Cleaner - Ash Greninja
However, the roles are rather flexible, as in some games, Ash- Greninja can function as a breaker if itG can transform early on, and Zygarde can become a sweeper, and Magearna the cleaner.
Ninetales EVs is to maximize bulk while always OHKO-ing standard defensive Pelipper on rain 100% with Freeze Dry. You may have noticed Safeguard there, and it's role is
1. To make it easier to switch into Wisps for Heracross when facing stall
2. Because HP Fire was the original, but never ended up clicking it.
Safeguard seemed like a fun gimmick, and has come in handy before, although the main move you will be clicking is always Freeze Dry. Encore is to prevent you from becoming total set-up fodder. It also helps potentially vs Smeargle leads, who might just spore turn 1, which can be totally negated with Safeguard. This can in turn make smeargle into complete set-up fodder.
I next decided to partner with Zygarde, because opposing Sun and Sand teams can easily make Ninetales deadweight by having slower weather. In these cases, I will generally lead with Zygarde, since it feasts on T-Tar and Char-Y, and thanks to Yache, doesn't have to fear the Ice Beam/Punch/HP Ice (first time at least).
Yache Berry also comes in handy vs things like lead Protean Greninja, who think they can gunk shot my Ninetales, and HP Ice Tapu Koko (dazzling gleam shouldn't OHKO either). When I see these mons, I will usually also lead Zygarde to get off damage with T-Arrows.
The set is very standard, Max attack T-Arrows as the main spammable move, DD to get enough power to cripple something for a future teammate sweep.
I have toxic, since I don't run Ice Beam on Magearna, so this can slowly wittle down opposing Zygarde without locking myself into Outrage, Tangrowth, and Lando-T. Also annoys Tapu Bulu, but less so thanks to Grassy Terrain.
My second breaker is Mega-Heracross. This mon is my favorite mega, and it's been that way since I first started playing XY. That natural bulk is even more terrifying under Aurora Veil, and it serves as my main win-con against stall and slower bulkier teams. It's generally able to get 1 or 2 kills under screens, and its also my main way of eating up bulky grass types which are this teams main enemy. However, getting it in on a bulky grass basically can equate to one dead mon on the other team. If you're lucky and can get a safeguard up, you can be sort of reckless with Heracross, at least throwing it into a scald won't be bad.
I made the EVs to outspeed 16 Speed defensive Landorus-T, but you can play around with max speed if you feel the need to. I appreciate the bulk though, and the extra attack that adamant gives, but 252 Jolly is an option. This mon is also my main answer to opposing Zygardes, which fail to even tickle it if screens are up, and they have to lock themselves into Outrage, which then gives Magearna time to set up if they are sufficiently weakened. It's also my only ground resist whoops.
Nothing to say about Magearna other than the fact it snowballs so damn quickly, and that you better pray you have enough bulk to not get 2HKO'd. It can SG on so many things, and is my main Greninja and Tapu Lele check which would otherwise destroy this team (0 switch ins to Ash ninja). I chose Flash Cannon over Ice Beam because I felt that bulkier grounds could be wittled away by combined power of Zygarde and Heracross, and also because unaware Clefable took pitiful damage from Heracross. Also, having that STAB for neutral hits is very nice. Might play around with Corkscrew Crash over All Out Pummeling for z-move to better answer grass types.
The Mew set is really fun and probably one of my favorite sets I've played with. The original idea was that I needed SR somewhere, but didn't want use Landorus-T. One probably could use defensive Lando-T as a good pivot, but so far Mew has not dissapointed. It lures in Fini, Scizor, Ferrothron, sometimes Lando-T, and even Tangrowth, and bonks each and every one of them with a coverage.
Finally, Ash-ninja does what it does best, and is a nightmare against opposing offensive teams. Against balanced teams, if I can break past the defensive backbones with Heracross, the rest is usually easily handled by Water Shruiken spam.