RE: Help building Sandstorm team
Honestly, I would ditch Lucario in favor of Keldeo. Keldeo is amazing at keeping sun and hail at bay while also acting as a great rain threat. Assuming that you use their most common sets, here's what I suggest:
SDef Tyranitar
Scarf Keldeo
SD Excadrill / Band Terrakion
Yache SD Garchomp
Life Orb Tank Latias
SDef Jirachi
Tyranitar gives you a reliable Stealth Rock setter and weather starter. You may even like Hippowdon better due to its better survivability and synergy with Jirachi. Keldeo I talked about above the team list. SD Excadrill (when with friends) is your prime sweeper, and its unfairly powerful and speedy. In its place, Band Terrakion provides you with what may be the best Band user in the game, capable of tearing apart walls for Garchomp to sweep. Yache Garchomp acts a good failsafe for Mamoswine, who looks like a threat to your team outside of Terrakion and Keldeo. He is your secondary sweeper if using Excadrill and primary if using Terrakion. LO Latias is a great offensive tank that helps with sun and rain teams. It essentially takes out all of the weather stuff that threatens you and helpfully walls special Landorus and Thundurus-T. Finally, I would put SDef Jirachi in your last spot. It's a great wrap-up in this team, helping with insurance against Tornadus(-T) and opposing Lati@s. I don't like Reuniclus nowadays because its only good set is Trick Room, which REALLY counteracts your team. Lucario is also underwhelming now with the powercreep and abundance of Keldeo and Breloom.
Hope I helped. Feel free to customize that skeleton as you see fit. Other good sand Pokemon include Rotom-W, Celebi, Breloom, Cradily, Stoutland, Sandslash, Latios, Heatran, Jellicent, etc. It's a fairly customizable weather.
~AoH