I've always liked the use of mismatched dining chairs and have collected lots of pics of rooms where they've done this, BUT, and this is a huge BUT, it depends on the rest of the decor whether it will work if the chairs are quite diverse. It only works IMO in a casual, cottage, eclectic, even funky room or if the chairs are reasonably similar in style. Trying to use mismatched chairs in a more formal traditional dining room will just look like you didn't have enough chairs and borrowed more. The only time it works, again IMO, in a traditional formal room is when the chairs at the ends of the table are (usually) upholstered and the other chairs are not, but of a similar style. Painting mismatched chairs all the same color is another possibility to create unity. If you find chairs with simple clean lines I think it can work. In my casual dining area, especially when there are more than 6 people, I use some black painted chairs. The 6 chairs are oak and part of my DR set and the black chairs are painted the same as a sideboard in the adjoining kitchen so it's almost as if there are 2 'sets'. Works for me in my casual home. Check out the link below to see most of the rooms are casual, cottage, and/or eclectic altho there are a few modern and European rooms as well. Here is a link that might be useful: mismatched dining room chairs

There are different "types" of microfiber; I would test it before you buy it. I had a settee/bench from Crate & Barrel that cleaned up easily with baby wipes (it was next to my kids "art center" and was stained with paint, markers, ballpoint pen, etc...). I know someone else who had a microfiber couch that spotted when you cleaned it. Have you considered leather? We have leather Pullman barstools and chairs from Crate & Barrel for our dining table. They are 4+ years old and have taken much abuse (similar to your situation) and have no stains or marks on them.

Man, I had to look at pic several times with diff posters commenting about diff elements, always so observant you guys. I have never considered fabric upholstery in the dining room or a rug b/c concerned about cleanup, and I've have some messes! About diff color wood, my table is totally diff than my chairs but ALL chairs match. Maybe if this lady added a plant stand or some other small furniture in the same dark stain as the upholstered chairs, it would look more cohesive, dunno. don't mind people enhancing the AFTER pic with flowers, pretty towels in a bath, etc. Or should we expect dirty dishes sitting in the brand new decorated room for a "lived in" view?????

Okay, I understand your question. No, I would not use an arm chair between side chairs on the sides of a dining room table. Also, before considering any chairs I would want to know the maker (often easily found by looking underneath the chair) and the scale/dimensions. Sellers are usually prepared to answer those questions.