Here is what I was thinking:
chum3- suicide
truddy02- Darkness duo (should work pretty good against any of the 3 decks they used last round, has healing and the ability to steal discords, may be a bit weak against titan rainbow)
Gyrodiot- Earth duo (I think it is likely that try the stall again and this would crush it, against the rainbow it is a bit weak)
Pervepic- Aether duo (risky against poison but they only used poison in a few decks last round but works well against a CC/bonewall deck which they have used more often including many times against us, darkness duo just doesn't do well against bonewalls because you never get to heal)
QuantumT- UG deck (water has mirror shield and I believe they are likely to use a similar deck to the one they used against us last time, gravity has no reflecting shields and seemingly none to little PC, also QuantumT has a nymph)
Klaymore- Fire duo (They are unlikely to use their air deck against us and immo can help if they use discord/BH)
We are limited in decks so it is hard to come up with a counter to all possibilities so you have to make somewhat of an educated guess of what we will be up against. Aether against death may be the riskiest but it does counter a handful of their decks. The other possibility is to swap mine and perv, then we are weak against death using a bone wall deck. I think the decks listed above give us the best chance to win the most matches. I think it is better to risk aether against death than darkness against death. I haven't done any tests so these are just my opinions from looking at decks.