Wow! Everybody here seems to like a lot of filtration!
The ac 110's are doing 500 gallons an hour each, so that's 1000 gallons an hour. That means that a 125 gallon tank is being completely filtered 8 times an hour. I think that that would be just fine for malawis. I would just stay with the 2 110's and nix the airstone, but that's just my opinion. Of course the more filtration the better, but if you have qualms about the fluval, I would think your just fine without it.