You are using almost the same thing I used in my team, and I could beat until everything before Amaria without exchanges. I'll try to build your team with what you have plus giving coverage to all types, just like I built mine
Blaziko+ Speed Boost is extremely strong, I used exactly the moveset you are using, worked well for me. Types covered: Bug, Grass, Ice, Steel, Dark, Normal, Rock
Exa would only benefit of Sand Rush in a Sandstorm team, you would need two turns to set it up (sandstorm + SD) and it's defenses are not so good so I would go with Mold Breaker and Iron Head in place of Sandstorm (as suggested). Types covered: Electric, Fire, Poison, Flying, Fairy.
Techinician Rosy is the best! I can assure you. If you are going to breed, mind Extrasensory and maybe HP [Fire]. Types Covered: Water, Ground.
For Umbreon, it's really defensive, not my type of pokemon, so I can't tell much. I usually see people using it as a support for the team. If Umbreon is used as attacker it would cover Ghost and Psychic.
We still have to deal with Dragon and FIght
For the last two slots I'd suggest:
Ampharos. Good movepool strong and Bulky. A good moveset would be: Electric Terrain or Rock Gem, Signal Beam or Thunder Wave, Discharge and Dragon Pulse. Types Covered: Dragon.
For the last Slot I would suggest a Flying Pokemon. Let's assume your Umbreon will not attack at all, so we would still need to deal with Ghost and Psychic (again, I don't know how to use Umbreon in a team), so for that reason, I suggest Honchkrow, it's type cover everything left + Moxie Ability, makes it great. It's a little restrict in moves but for your team it would be good. Moveset: Brave Bird or Drill Peck, Night Slash, Roost and TailWind.
If you need, I can help you with breedings. Also I have some Murkrows with Drill Peck and Roost as Egg moves, not good IVs though.
Hope it helped