At the very least, definitely put the grill covers on the Wilsons. If the speakers in any way protrude into a walking path, consider moving them closer together or closer to walls. Open houses can get busy, and there are often growing families where children are not always monitored. All it takes is one toy scraping on the side of your speakers to make you regret not packing them.
I agree with others that a staged environment helps more than hurts, and your setup is fairly minimal and looks sophisticated. Little details like that gives prospective buyers a quality of your character, which adds to the confidence of buying the property.
Best of luck!