The set is quite good actually. I would personally use a Bulk Up set, but I guess its fine.
Ah, a common mistake. Talonflame actually would prefer not that much speed because it would likely be using its flying types moves more often.
The reason why we use Flying Gem is because its accrobatic is a priority move and acrobatic will be boosted both by flying gem and the loss of item. With Brave Bird, Leftovers or Shpar Beak is prefered.
Now, its REALLY PISSING ME OFF @IndianAnimator ! TELL ME WHY DO YOU KEEP PUTTING THAT KIND IS SPREAD GOD DAMMIT!
Latias should be run with Max speed. If you don’t use Healing Wish, its hard to justify using Latias over Latios.
I already told you about the Choice Scarf + Swords Dance. But do you really want Mold Breaker without Sand Rush? Its a real question, telling Yes is totally viable.
Gengar have a bulk beyond saving. ALWAYS put Max Speed and Timid.
Tyranitar have very low speed and it is often better to put some HP. I suggest you go see my analysis on Tyranitar to see what is better for you. Look for those of the Jaw Breaker set.