I've recently bought some Laminate wood flooring for my basement (not yet installed) and have a few concerns.

Synopsis: This is a typical basement, drywalled, drop ceiling, concrete floor currently covered with carpet and ceramic title. Drain pipe located in titled room and will NOT be putting laminate near laundry area. Basement sometimes a little musty/damp in summer, dehumidifier fixes that though. Never had a water leak, though noticed some brown spots creeping up the wall an inch or two in one corner of the tiled room, looks like rusty water stain.

My concerns are:
1. Wood laminate is OK to use if basement doesn't have leaks, correct?
2. Should a "moisture test" be preformed in each room, or just one?
3. How likely is it that moisture will come up through that drain, and can I seal or get a special cover?
4. Should I seal the concrete flooring or leave as is?
5. The underlay is specially made for basements, with foam on the bottom and plastic on the top. Will this cause any molding?
6. Also, I was planning to lay the laminate right over the tiled room, remove any carpet in the other, put down some sheets of plywood to compensate height difference once the carpet is removed so both room are same height. Will that cause me problems, or should I remove the tile and lay down on concrete?

A friend of mine is in real estate and says the question is not will my basement flood but when will it flood. You can lay a moisture barrier down before the padding but that will not help you one bit if you get as much as 1/16" of water in the basement in any area or spot. Your padding appears to have a moisture barrier but I think you may have top and bottom mixed, correct me if I'm wrong after reading the manufacturers instruction booklet. I can honestly tell you that I no of no one who put laminate in their basement, like your< and was happy 4 years later. Armstrong does make a vinyl tile the shape and size and look of laminate flooring. It requires no gluing and does work well in basements.