I don't have to much experience with sand, but I'll try.
I like your set, but IMO, it is outclassed by this set from smogon:
Tyranitar - physical sweeper - Lum berry
EVs: 252 atk, 252 speed, 4 HP
Ability: sand stream
Dragon dance (description below)
Stone edge (^^)
Fire punch/aqua tail/ice punch (^^)
Merely the fact that Tyranitar had Dragon Dance in its repertoire allowed it to see some use last generation. However, with the advent of Black and White, it is much less common, which is perhaps, if anything, a boon to this set, making it more unpredictable. Dragon Dance resolves the problem of Tyranitar's middling Speed, allowing it to outspeed a variety of threats including Starmie and Latios after a boost. From there, the bonus to Attack is all but overkill; many teams just may struggle to find an answer to +1/+1 Tyranitar. The two STAB moves are obvious choices, but the last moveslot contains a variety of options. Fire Punch allows Tyranitar to nail Ferrothorn and Scizor. Scizor should be hit while it attempts to switch in, however, as it could otherwise pose a threat with Bullet Punch. Aqua Tail grants you a reliable way of touching Tyranitar, Gliscor, and Hippowdon, while Ice Punch delivers a much more commendable dent to Landorus and Gliscor.
Excadrill looks great except for return, which I would replace for rapid spin, to spin away hazards and such. Also, your sand rush + adamant thing is great, but my personal preference is sand force + jolly, as he is already wicked fast.
I like your Latias set, but 164 might not OHKO terrakion due to the fact that his special defense is boosted by sand, however, with pays hock it just might. I would try this set, which is a wall breaker/sweeper set, and puts blissey on its death bed:
Latias - wallbreaker/sweeper - choice scarf
EVs: 252 sp. def, 252 sp. atk, 4 spd
Trick (gives your opponent a scarf, locking them into the same move, shuts down walls and tanks such as blissey)
Calm mind (allows him to boost stats while your opponent switches to something that isn't scarfed)
Dragon pulse (STAB)
Psyshock (STAB, eliminates special walls)
Your breloom looks so great I actually cried tears of joy (not really). But it really is perfect, don't change it.
There are two options for heatran, if you want to keep the scarf then keep your current set, but if you want to try something a little different then use this special based annoyer/staller set from smogon:
heatran - staller - leftovers
EVs: 244 HP, 44 sp. def, 220 spd
Ability: flame body
Torment (description below)
Lava plume (^^)
This is the notorious Torment Heatran set that once upon a time made players rip their hair, gouge out their eyeballs, and jump out of a window as soon as they encountered it. The idea behind the set is that very few Pokemon carry more than one attack that can severely hurt Heatran, and by using Torment on them, said Pokemon must either switch out or stay in and engage in a long, brutal stall war. Pokemon who wield a Choice item are especially affected by Torment, for they must Struggle every other turn if they choose to stay in. Substitute and Protect allows Heatran to both scout and shield itself from moves that can harm it. Lava Plume is chosen so that Heatran can slowly chip away the opponent's health.
Garchomp looks great!
Hope I helped!