Who would be good teammates for Skeledirge if I were to use him competitively? How about Meowscarada teammates?
When it comes to OU...
Meowscarada can do fun things like threaten Dragapult out with Sucker Punch, set hazards, remove items with Knock Off, scare other Dark-types with Play Rough, dump on Grass-weaks, and U-turn like the dickens, so other mons that appreciate hazards (especially throwing in a Pult-weak partner) are likely good teammates. I'm kinda thinking that whoever appreciated Greninja (probably a lot of mons, especially since Toxic Spikes enables some stallier stuff with less coverage) is fairly likely to appreciate Meowscarada.
I'm less confident about my ability to find good teammates for Skeledirge. I ran some calcs lately that indicate that Gholdengo, who shares quite a lot of resists and immunities of 2-type combos with Skeledirge (e.g. Fairy + Fighting, Steel + Fighting, Bug + Fighting), can actually guaranteed OHKO the Fairies it's supposed to check (and at least one Fairy it's not supposed to check but somehow sometimes can) with Make It Rain even with a defensive set, while Skeledirge needs to either go offensive or use Overheat and Special Attack investment to do the same with Bugs (e.g. Slither Wing) and Steels (e.g. Magearna - Specs Magnezone gets barely guaranteed OHKOd by Fire Blast, Tinkaton cannot 2HKO). Admittedly, Will-o-Wisp is a pretty good way to cripple randoms, but Choice Band/sun/Booster Energy Slither Wing can 2HKO Skeledirge with Earthquake even when burned after the first attack(!!).
Considering that Skeledirge might be going offensive anyway, teammates that beat Darks, faster Ghosts, Grounds, Waters, and Rocks are appreciated. Ironically, Meowscarada actually makes a good teammate for Skeledirge. The fastest Ghosts and other faster/Sucker Punch Darks make decent partners, such as Dragapult, Flutter Mane, Chien-Pao, and Bisharp/Kingambit. Waters also make decent partners, such as Palafin and Quaquaval (the irony again). Lastly, Fairies such as Iron Valiant can also help with the Dark problem.
(As an aside, with Chien-Pao being this threatening right off the bat and Kingambit insurance being appreciated, Quaquaval seems more like a guy who fills holes and partners with others than someone to build around and find teammates for.)