Tile and mortar are not effected to the degree of failure, as wood is to moisture, if at all.

How many swimming pools have you seen with tile, submerged in water?

good point. I will remove some tiles and do the testing. I do not want to remove them all however. If I have to I have to. Its Lauzon, and their tech person said its okay on tile. This is in Florida. Good drainage. Gutters with water directed away from the house.

Any other comments or pointers? I appreciate all the input. Very helpful. Don't want to need Ray to come out and have to say I told you so.( Ray, I am in Clearwater.)

Ceramic tile is an approved substrate. I stand corrected. My memories of ceramic tile as a suitable substrate is that of failures during my retail days as the adhesives required the ability to dry in all directions. Have not seen this procedure in a long time...
the "floor guy" is correct according to NOFMA and adheisve manufacturers.

Sandy,
If your home is in Clearwater, there is a good chance it was built in the 50's through 70's. The soils build up along side the perimeter of the slab over time. Should your soils be high along the foundation, you'll have excessive vapor emissions through the slab.
You are wise in performing the tests prior to installing the wood flooring. Did you check clearances to make sure the thickness of the wood will not interfere with Doors, dishwasher clearance, thresholds, closet doors and so on?
Since being in Florida, I'be seen no installations of wood direct to ceramic tile which means it seldom fails or the practice is seldom used. I'll have to dig into my memory as to why I have such negative thoughts about wood over ceramic tile.

I remembered!!
Two failures seen.
1. The tile was not the problem; It was the grout. The grout cracked out along the perimeter of the room. I remember the complaint being "loose and crunching sounds". We lifted the floor and found the grout pulled out. Apparantly the shrink and swell of the wood pulled the grout out.
2. Debonding. The glue on the back of the planks had the trowel ridges but the wood, with the adhesive on the back of the planks, had de-bonded from the tile surface. Tested the adhesive and the top of the tile to find High Alkalinity. I could see the glue stains on the tile surface so I knew the bond was there after installation. Tile is porous which allows absorption of the cleaning agents. Covering the tile resulted in the vapor emissions bringing cleaning salts upward and degraded the adhesive at the bonding point. The adhesive still had good grab onto the grout, but not the face of the tile. I honestly don't remember all the details of each failure but these failures left me with the impression to not adhere to ceramic tile or stone.
You may ask why we see so few failures on this issue.. I think Marco has the right answer about a floating floor. The past 8 to 10 years, floating floors have been the answer and the most common practice used in this situation. I don't think there are many installlations with wood glued direct to ceramic or stone which is why inspectors see few failures.
We have recently moved into our new home and most of the reference materials are still in boxes leaving me to use memory. I know Perry has the "Bruce" books and Marco placed a link to NOFMA stating ceramic as an approved substrate. I wonder if they give clearly stated directions on floor preparation of the ceramic tile for the purpose of adhering wood???
Marco, in my opinion, has the best advice for you. The Sound can be minimized with the use of firm/hard cushion and the transition trims are available to use at the ceramic tile. Before adhering wood to tile, I would urge you to think about Marco's suggestion of using a floating floor method.

Thank you Ray. My house was built in 1984. I will check to see if the soil is built up over past the slab which I would think it would be. My clearances are okay.

I did already purchase the product and don't think it can be floated. If worse comes to worse, I can have the tile removed. If the tile is flat, wouldn't the slab under it be flat?

A couple of questions:

Would doing a skim coat over the tile avoid the problem of the salts rising etc that you described? Are the adhesives that are now out different from the ones used on the failed floors?

When you remove the tile the thinset is the hardest to remove- do you have to remove it all or can you float something over it to level it?

Skim coating will not help. Skim coating may not adhere to the tile surface unless tile is sanded. Skim coating over smooth surface may result in de-bonding. Just fill the grout lines.
The tile being flat means the tile is flat. The concrete underneath may not be flat.
Have fun Sandy.

and....if we sand the tile, then do the skim coat, that should do it right?

I called Lauzon and they say its okay with Bostics Best MVP or with their "Next Seaker abd Bext Grip adhesive.