Filtering Noise on Strain Gauge Circuit
You should take full advantage of your bridge to directly drive a difference amplifier. Trying to create the separate reference of 2.47V using an LM324 is going to be a source of error that will likely forever kill the performance of your circuit. After all there is a good reason that full bridges are designed into load cells.

I've not looked at any data sheets for the parts that you are using but it also seems like your use of the ADxxx parts for part of the circuit and the LM324 for the references will be another source of error. The LM324 and the ADxxx parts are likely to be in completely different leagues when it comes to error parameters such as the offset voltages.

Another thing to think about. When you get your circuit all polished out there will still be an error where zero load not equal to zero result. The best you hope for is that the total circuit is as linear as possible across its usable range. Then you take what ever reading you get at "no load" and subtract that value from readings that you make at weighing time to get the actual weight. Another factor to add into this is that it is often necessary to also use software to scale the readings to actual weight. This entails taking a reading at full weight and storing that to be used to scale subsequent readings to actual weight. 

If you are unable to achieve good linearity of the analog circuitry over the full weight usage range it may then be necessary to additionally calibrate the system at additional points such as mid range or at 25%, 50% and 75% to give the ability to scale readings to actual weight by doing linear interpolation over shorter sections of the input range.

Lastly do not discount the importance of what temperature variation will do to your system.