Since you have a basement underneath, and depending on whether accessibility from directly beneath the floor is easily accomplished, you may be able to additionally counter unforeseen issues through further reinforcing the floor. Your immediate concern appears to be floor covering versus the actual floor, and none of your selections actually add to the strength of the floor; very little, if any. Ceramic tile can crack it installed on an improper sub-base, synthetic tile yields a variety of very attractive choices, linoleum is an unsung hero of flooring for its durability. You did not mention the area you are covering? Just the laundry area, the kitchen, or both? Go with what pleases you best, and what you can live with for several years. Here is a good thread to better inform you about floor issues: Miele 4840 Vibration - Damaging homes?

Measure the depth of the washer and dryer to determine the depth of the countertop. Leave about 6 inches for the water-hose connections and the dryer vent. Measure for the height of the counter, leaving about an inch between the counter and the appliances.

It depends on where your water faucets (to/from the washing machine) are -- but generally, if you can connect them, you should be able to move them 3 or 4 feet without much function loss. Of course, you might see the connection hoses if you do.

I guess I will chime in here. We have front loader machines and they sit and are bolted to pedestals purchased to fit the machines. I have all sitting on a rubber mat. That said, the installers were very particular in leveling the machines and they do not move at all. Even with big loads (mine is high capacity) or small loads...no walking at all. Yes, the washer vibrates a little, but doesn't move and is not noisy at all. The laundry room is in a room off our kitchen and there is basement under the laundry room. The pedestals are handy for putting cleaning cloths in one and the other for laundry/cleaning products.