Scarf Scyther outspeeds Unburden boosted Swirl and always lives an ice shard from Sneasel, everything it doesn't naturally one shot only needs to take damage from Ferroseed recoil and it will be put in range. Works equally well as a lead as it does a sweeper, but it most commonly does the latter
Swirlix is there to be a swirlix but I have never brought it to a battle because I haven't needed it, it does make predicting what my opp will bring a little easier, and I can support it easily with Memento from Diglett, it just hasn't come in handy yet ¯\_(ツ)_/¯ I've got flamethrower to hit opposing Ferroseed but it doesn't OHKO so look out for that
Ferroseed is the MVP of the team, it comes in on many physical threats and puts them easily in range of scyther and fletch, or just outright beats them. Beats swirlix, sneasel, and a whole lot more 1v1. You pretty much need a ferroseed on your team or really strong answers to it.
Diglett is solid for playing against sun. Trap Vulpix, and win with Ferro (unless Hp Fire tangela) and/or Fletch. Thanks to Diglett, Sun turns into from a frightening matchup to a fairly easy one. Another great lead.
Fletchling is responsible for most of my KOs, it forces out big threats like Scyther and Yanma and can just sweep entire teams with SD from lead occasionally. Ferroseed is a great partner because it puts everything in range of Acrobatics after it takes recoil. Fletch is another mon you need on your team and need to heavily prepare for, probably the individually best mon in the meta. I had roost over HP grass initially but roost never came in handy. Stealth rocks are terribad in this meta so having 2 mons weak to rocks is not an issue. Leads or Sweeps.
Meditite is a solid mon, I was lacking a reliable mon to beat overheat Fletch so I've given meditite Coba Berry to survive an Acrobatics and KO back with HJK. The second most expendable member of the team. Meditite also serves as a check to ferroseed and can get valuable chip damage or revenge KOs with Fake Out + BP