Hm, 2 water, 2 fire, and 2 grass. I can think of a good combo being jellicent, heatran, and breloom. That gives you one of each type so far and gives you a core that covers several types. You can never go wrong with suicune and shaymin as 2 others either with a good range of coverage and defense. If it wasn't for possibility of rocks or other heatran I would suggest volcarona, but in this case I'd suggest Arcanine or Darmanitan to cover the last bit of physical power. It's a little special heavy, but in theory they have a wide range of coverage with move pools, don't need a real set up, and can deal damage against others of similar types.
In other news just like smogon, PO held a vote on a ban for snow cloak/sand veil and genesect. Both ended up being banned. 33 people were allowed to vote and I know that for genesect only 8 votes were counted because they required paragraphs detailing why they believed it was broken or not, and it ended up being 4 bans, 1 no ban, and 3 abstains. Really close voting and goes to show how much people suck at explaining why something could be broken or not with a lack of back up statements. One guy even compared Gene's attacking stats to arceus which means that anything with 120 or higher attacking stats should auto be uber material...SMH against a lot of people. Honestly, I don't find it broke as it is one of the few counters to my teams I have so it was a much needed balancer, but I guess for the mass of people they aren't able to handle the thing. I don't remember the numbers for the sand veil ban, but it was more one sided with more votes I think.