Random Matchup consists of 3v3 singles, 4v4 Doubles/Rotations, or 6v6 Triples. In these formats, entry hazards like Stealth Rock generally aren't worth the move slot since the match will be over so quickly.
I could go through the many errors with this team, but generally, you picked 6 random Pokemon and gave them 4 random moves each with no real rhyme, reason, or strategy. You need to keep in mind that, generally, these battles will be over fast and set up isn't a good strategy and defensive tactics better require some REALLY good thinking on your part or your opponent is just going to beat on you while you set up. I know Random Match doesn't let you give the same items to your 6 Pokemon, but no one should be using the gems unless it is a situational thing like Acrobatics Flying Gem Gliscor or something. Life Orb, Choice Band, Wise Glasses, etc... are always a much better item.