Since this is an outer wall, I'll wager this is thermal expansion/contraction of the piping or heating elements. When I was very young, the house had a family room that had been converted from a screened porch. A loop of hydronic baseboard heat was the easiest to add to a system that had radiators elsewhere. As the heat would come on, one could hear the baseboards creaking with expansion, which would occur sequentially around the room. Sounded like some small and not especially energetic critter making the rounds. If you don't see droppings, you don't have mice. Snakes, maybe, but not mice.... ;-) Cheers

Definitely use the felt pads and buy at least 4 of the sliders your friend mentioned. The sliders (without the covers) can even be used when moving furniture on carpet. I use the felt pads on the feet of my breakfast chairs and replace them every few months. Grit/dirt will collect in the felt pads and they will slowly scratch the floor if not changed out over time. So far, no scratches on the floor under my chairs! I've also used towels in the past but be warned that a heavy piece of furniture may still leave a mark when using them. I learned that the hard way when I moved a small table across my floor. Fortunately, I had only gone about 4 feet and just happened to stop to make sure nothing was being damaged. It left an indentation about 1/8" wide.

Your floors can possibly be recoated, and if it works, it's has advantages over resanding. A six year old floor shouldn't need resanding. I've had decent results prepping and recoating AO floors but I limit my work to floors I installed. Using the wrong maintenance products can hinder the adhesion of a new coat, even when you follow the proper preparation steps. What has the floor been maintained with? Your statement that it shows every speck of dust and footprints, makes me wary. Maybe you're exaggerating a bit, or perhaps the floor was coated with something that is causing that issue. Do you have any original unused flooring? If so, how does the gloss level compare to your floor? I looked up their Brazilian Cherry and only see it offered in a matte finish but the product may have changed since yours was purchased.

Even the water based polyurethanes require sanding prior to use. The sanding machines are going to be LOUD. If you are BELOW them you are going to think their machines are going to come down on your head at ANY minute. It would be best to take a day or two off and be elsewhere while the work is happening. I like to see customers stay in town during a flooring refinish. It means they are close enough to visit the site in the morning and evening. They can keep an eye on progress and are within a short drive should the installers come across something unusual that needs the owner to view it and then approve it. Dogs are territorial. They can be traumatized by super loud events in their home that they are not allowed to 'deal with' (ie. not allowed to bark, not allowed to chase the people away, etc). Again it is a good idea to have dogs and cats out of the space while the work is being done. The 'fumes' of the water based polyurethanes can be bad (if your finishers went cheap) or it can be tough but with enough dry time/airing out time it is livable within a day (high priced stuff). Without knowing what product you are getting on your floors, we cannot comment any further on odour. Odour is the number 1 cause for homeowners to leave the house for the first few nights after the job is finished (and the nights DURING the work). Again, the PRODUCT dictates odour...not your nose or your lungs. Personally I would make sure I have a stay-cation during the work/application of the finishes. And remember: the colder it gets the longer it takes for the finishes to cure and the less likely you are to open up all the windows (yet keep the heat pumping) to let the house air out. All of those factors will add up. Dogs' noses are many thousand times more sensitive than ours and their lungs are smaller. That means they can have more issues then humans when it comes to odour and off-gassing. Cats are the same. Besides, you need to stay off the floors until the full cure happens. The dogs have to as well....and the furniture. Area rugs are to stay off for SEVERAL months (many refinishers will tell you to leave the rugs off the floor for 6 months or more). As you can see, all of this adds up to the decision to leave the home (overnight stays) during work and while the floor is curing/off-gassing. Please tell us which finish you have paid for.