You have a ton of questions and I will do my best to address them, I also have AADD so if I start to ramble and jump back and forth just overlook that :). We need to simplify this more because there are certain issues you can't change..... being on a slab and the weight issues. Any slab has to be reasonably flat and dry, but in your case it needs to be almost dead flat and dry. We are supposed to always check slabs for vapor emissions that can go unoticed when there is carpet over top that allows the slab to breath and release moisture without any problems. You have an 18yr. old glued down wood floor that has exhibited no problems, in my view that is as good an indicator one is going to get..... so we'll just say you are dry. I don't know how many sq.ft. is involved but it takes some space for an installer to check the slab for flatness and then take measures to correct it. Sometimes a low spot can be a few feet in diameter and with the feathering needed I may need 6', 8' or more to deal with it. If I don't have space I could be featuring up to a high spot underneath furniture. It is best to try and figure a way to go one room a time, clean it out, then go on to the next room. If you have your heart set on an engineered BC, then get it :), life is too short to fret over that as long as you know about this issue and are okay with it. On glued down floors the thickness does not really matter as much as opposed to floating. What does matter is the top wear layer thickness and using the right adhesive. A 3mm or 4mm thick wear layer is actually better in the long run as a 5mm thick . Going too thick with the wear layer can cause a phenomenon called "dry cupping" .... the NWFA and NOFMA are aware of this and it is being addressed. If you go with a glued down engineered wood floor and want to put on a sealer as "insurance" , then do it. In your case I would strongly consider using Stauf 960 which is a quality sealer and adhesive combined in one application. You pay alot more for the adhesive but you only have one labor issue. Imo you could also go with a floating floor. But to pull this off you must use a quality product and (here I go again)..... the concrete must be flat. There is a laminate out there that I have personally installed that is almost bullet proof. That would be Wilsonart , which is a high pressure laminate referred to as an HPL. Putting that down along with using their blue fusion glue in the joinery can take any weight you want to put on top of it. When I do that I recommend to the client upgrading the underlayment to a product Sound Solutions. You cannot walk on this type of install and tell that it floats. You could also go with a floating engineered wood... this is where thickness comes into play. I prefer to use nothing less than a 1/2" in thickness and a where the joints get glued up, or, choose a good reliable click-lock system like the valinge or Uniclic joinery systems. They both hold together well. The wood should also be waht is called balanced.... the top layer equals the bottom. You are very typical of alot of my clients. Quit stressing so much :).

check out DDCC laminate its all 12mm and they offer a huge selection.

Heidi It comes in two other neutrals http://www.porcelanosa-usa.com/products/tile/stonker-porcelain-tiles.html I didn't do patterned encaustic cement tiles because, among other things, ensuring that the thickness of that tile seamlessly transitioned to my hardwood floors was a concern in my 1906 formerly commercial space. I know they require initial sealing but am not sure about ongoing sealing. I avoided ceramic tiles because of durability concerns (chipping). There are other porcelain tiles printed to look like encaustic - not a lot, but worth looking for because they are most durable option. These are $8 sq ft. Only some of the patterns shown are imported into the US. http://www.malinetile.com/tile-vives-vodevil.asp These folks make many patterned tiles, but check the tile composition https://www.somertile.com/

I would use the same wood. Marble look tile can look good in the public rooms of a super modern house in Miami, but not as good in your average suburban home.