The impact of seating configuration on aircraft stability

[Wrist Watch]

I've been wondering about this.

What are the effects of 2-3 (or 1-2) seating configurations (on A/C such as MD80, EMB135, CS100, etc.) on lateral stability and centre of gravity?

I would assume not much because the additional seats lie almost directly above the longitudinal axis so not a lot of moment would be produced.

But still, is that 'imbalance' still actively offset somehow, for example with cargo location or fuel (re)distribution?

Thanks.