Ech, I don't like Bounce on Gyara, it lets nasty stuff come in on you when forcing a switch on one threat isn't enough. Taunt or Earthquake would probably help you more. If Taunt, use a bulkier spread (156 HP/108 Atk/100 Def/144 Spd).
On Latias, go with Refresh > Thunderbolt. It turns people...