If your slab as wet as your described, I would certainly recommend to use MVP or something similar to seal it first, then Floor Muffler, then float your engineered T&G floor on top. I want to talk a more about your floating T&G engineered flooring. These types of multiply engineered wood floorings are usually designed for glueing down application when solid hardwood flooring are not suitable to use, such as in a condo project,basement or main floor slab subfloor. So the tongue and groove are usually not milled tight enough to hold the T&G in place after the edge gluing. So the boards will tend to separate before the glue dries. If it is random length products, installation will be even harder with some boards are shorter. However most of the engineered flooring brands allow to float their flooring to cover more market or applications. To me it may not be a good choice for DIY home owners simply because they are not as easy as the traditional European style longstrip 3 ply floating wood floors to install. Even without Click Lock system, a T&G 3 ply engineered wood floors are very tight to tap the tougue into the groove. So when glue applied in the upper part of the groove, the tongue will stay tight once tapped into the groove. I guess this is the difference between an engineered wood floor and an engineered floating wood floor, which we are asked all the time by confused consumers. So the answer to your quesiton is: If the tongue and groove is tight, you can edge glue without using the strap. If not, you'd better strap them.I hope my 2 cents will help.

Even without knowing the kind of wood or condition, I can't imagine replacing wood flooring in an 1890 home. In my opinion, the value is in the original material. If the floor is in good condition, it may not need sanding at all; a screening and recoat might be all that's necessary and the patina would be retained. There are many threads on this topic, try searching the Old House forum. I live in a converted schoolhouse built in 1890. The fir floors had been covered with layers of linoleum, glue, paint ... they were a mess.. but looked awesome after refinishing. That was years ago and I'm planning to have them screened soon (aka buff and recoat.) What kind of wood is it? Do you have photos?

So since there is open space on all of the other sides of the wood, grouting will leave enough room for expansion?? I know engineered flooring isn't as susceptible to expanding/contracting. I didn't know that caulking an edge is still considered leaving a space (thought it had to be open). Does grout still allow the floor to move?? Are there any options for no transition piece if the wood floor and the tile are NOT the same height? Thank you for your response! :)

You can be sure those floors are Chinese, because they never mention "China" in their FAQ answer. Not that the floor is bad or good, it's just that China has a bad reputation. The fact that they have not responded to your request for more information is nearly proof positive.