Stainless steel bolts

Accidentally bought 2A Stainless steel bolts to replace the bolts for puma rear seats. I did a bit of research and have realised there's a lot of debate on use of steel vs stainless steel. I want to over time replace bolts in and was wondering what people think are the best options to permanently fasten parts that will last. Types of bolts, washer/ spacers, nuts grease or oil (other methods to prevent corrosion)

A2 stainless will be fine on anything non load bearing, slap some greae on the bolts when fitting to stop gauling and corrosion.