Your Talonflame set is really bad. Max HP investment gives it an even number so it can't switch into Stealth Rock more than once, and you are always going to be out-prioritized by other Talonflame, Mega Pinsir, and Thundurus. SD Talonflame should always run enough speed to beat Thundurus so it can OHKO it before getting T-Waved.Greninja Life Orb
Naive 252 speed, 44 attack, 212 special attack
Gunk Shot
Hydro Pump
Ice Beam
Dark Pulse
Talonflame sky Plate
Adamant, 252 attack, 252 HP, 4 speed
Brave Bird
Flare Blitz
Swords Dance
Roost
Both sets are very standard except my Talonflame who invests fully into bulk where normally he has a lot more speed investment, but that priority imo makes investing to much into speed not really worth it in the long run.
+2 252 Atk Sharp Beak Talonflame Brave Bird vs. 0 HP / 4 Def Thundurus: 228-268 (76.2 - 89.6%) -- guaranteed OHKO after Stealth Rock
The only time you shouldn't be running any speed is for Stallbreaker or Bulk Up sets, which appreciate the bulk and don't really need the Speed for what they try to accomplish.
Fire/Flying actually gives 6 resists, it's the double Rock weakness that kills it.252 HP talonflame? That sounds a little bi weird. It already has an awful defensive typing, and isn't bulky at all. I think you could be better off investing in speed, so you can outspeed other max speed talonflames. I've used this core to great success before, and I can testify that it's extremely effective against offense.