I did this a few years ago and it still looks good as new, but I recently read that its not recommended to use fix-it-all on the exterior of the home because it can absorb the moisture in the air and further rot the wood. 

The advantage of porcelain and vinyl in Arizona (as opposed to real wood), is that you don't have to worry about moisture issues (or lack thereof).

I recently had a tenant move out. He claims that in a spare bedroom, which was hidden by a bed, when he moved the bed out he discovered an extremely raised section of the hardwood floors. The "peak" of the raised sect...

Your contractors should do a moisture reading to see if there's anything inside the walls.

They also cause a lot more moisture in the air, fogging up the mirrors a lot faster, which is annoying to live with.  

The home is from 1960s and never had a moisture barrier so that’s where the damage is coming from. 

I was thinking the same thing - seems like the moisture is coming from the cooking itself and not exactly the fuel source.

My suspicion is there is ample moisture and you need to improve air circulation or determine the cause of it.

If you are worried about moisture have you used a moisture meter to see if there is a delta between that area and somewhere else on that wall? 

I went over to check it and there is just a tiny bit of moisture at the base.