OK, so they may still work... on Chomp. That's one Uber in check. Now you have wasted a pokémon slot just for chomp and there's still Kyogre, Groudon, Rayquaza, Dialga, Palkia, Darkrai, Mewtwo, Deoxys-A to name a few.
Also, you say your counters would have to be able to counter other things, but they can't. The Uber tier has a lot of pokés with base 150 (special) attack and it will hurt any OUs you use, even if they are as bulky as Suicune. Kyogre, Mewtwo, Palkia, Dialga and a lot more can easily switch in on Suicune and will KO it. Mamoswine has it similarly, except it can't already switch in on anything from Ubers without promptly being KOed a turn later. Ice Shard also probably doesn't do enough to OHKO Rayquaza.
Suspect is a separate ladder on Shoddy where pokémon who are being tested if they are Uber (Garchomp, Manaphy, Skymin-S, Latios) are allowed to play in, to test if they're not too centralizing.
And yes, those six sets are the only viable Garchomp sets. All Choice Sets use EQ/Outrage/Dragon Claw/Stone Edge. (in Ubers at least)