Owning your own home

You can get oil stains out of marble if you act quickly. A poultice of flour to draw as much as possible out and use a thinners type marble cleaner like lithofin OIL-EX. Basically rotate the two techniques. Use a lot of clean cloth, don't use kitchen towels with printed patterns, the dye runs. I've done it successfully but it took a few hours over a couple of days.

The worktop might benefit from some sticky backed aluminium sheet, the type that's used for glass to turn it into a mirror. The problem with wood/mdf is it needs to balance moisture in/out on both sides. The aluminium would protect against steam/heat but it would create an imbalance with the top which breathes more normally. Probably better than the situation you have now though. Glass shops have sheets of the mirrored foil.