Engineered floating floor

We have opened up some walls in our downstairs, so that now our living room flows into the kitchen in a large L shape, probably about 800 sq ft of space. We are now interested in putting down new hardwood floors. We are thinking of a floating hardwood, maybe Mannington. Because of the remodel, we have different subfloors, ranging from oak hardwood in the older sections to 3/4" plywood in the newer sections. In general, the plywood is installed level with the original oak floors, but of course there are slight variations where the floor meet each other. I don't think we are looking at more than 1/4", though. I know I'll have to sand down some rolls in the older floor and possibly fill some areas, but my questions are:

1) Are floating floors a reasonable solution going over various sub-floors with slight variations?

2) Do floating floors work well in that size space and transitioning from family room into kitchen? Or are they intended for smaller rooms.

3) In the kitchen, do we run the floating floor under the major appliances (range and refrigerator) or is it not intended to carry that much weight?

I actually have more questions, but I'll start with those three.

 

1) No! the specs for the flatness of the subfloor under the finished floor are pretty strict!
1/8" in 6' or 3/16" in 10'
Anything more will make noise & damage the planks when walked on.

2) Floating floors work well in any size area, as long as the manufacturers installation specifications are followed to the letter.

3) Yes, it is generally run under the fridge, and under the stove, and are excellent places for blimished boards, that were culled out during installation.