So after I got to the Battle Tree in Ultra Sun, I started putting a revised form of the Aron team I used a while back to work:
(M) @, Relaxed, Pressure
EVs: 252|0|4|0|252|0 / IVs: 31/30/31/31/31/0
Night Shade | Brick Break | Pain Split | Trick Room
(F) @ , Bold, Sturdy
Lv.1 Stats: 12|5|7|5|5|5
Endeavor | Protect | Toxic | Iron Head
(M) @ , Quiet, Pixilate
EVs: 252|0|4|252|0|0 / IVs: 31|0|31|31|31|0
Hyper Voice | Psyshock | Shadow Ball | Swift
(M) @ , Brave, Intimidate
EVs: 252|252|0|0|4|0 / IVs: 31|31|31|xx|31|0
Fake Out | High Jump Kick | Crunch | Detect
The main edits I made were changing the Trick Room setter and Scrafty's held item. Hitmontop was used briefly on a separate run in Pokemon Sun, but wasn't as good as I had hoped; it did help with my old team's Fighting-type weakness, but introduced a new issue in the form of being just a bit too fast. Needless to say, it was out. I went ahead and started breeding for a Dusclops to use in place of Porygon2 to rectify the Fighting-type weakness, while putting Scrafty back on the team carrying Darkinium Z instead. Dusclops helped quite a bit, mainly in the form of being extremely slow and, much like P2, extremely bulky. Darkinium Z Scrafty is a major help for lots of
Bullshit Powder Bright Powder carriers/Double Team users like Latias and Cresselia; those two used to be real pains given the resistance to All-Out Pummeling (and, in Cresselia's case, barely taking anything from Sylveon's Swift). Dusclops EVs are best explained by laziness.
Problems that definitely still exist: Z-moves and Scizor (also Skarmory to a lesser extent; mainly have a hard time handling Steels that don't have a Fighting weakness). Not a whole lot to do about Z-moves; those nerfed Aron hard and there's really not anything that Aron teams can do about that. I'm currently considering replacing either Sylveon or Scrafty with something with either Fire-type STAB or a decently powered Fire-type attack that would better equip the team against Pokemon like Scizor and Skarmory, as I currently depend a little too much on Endeavor to deal with those. Alternatively, breeding a Hidden Power Fire Sylveon would help, although HP Fire is a bit on the side of "really really weak." I might just do that, especially seeing as Shadow Ball hasn't seen any use as of yet.
I already got this team to 50 wins in Super Doubles and am now trying to bring it past my old record.