sealing a basement

I am finishing my basement with floating walls (I live in Colorado...), and have a couple of questions. None of the walls being built will be load-bearing. 1-Can a floating wall "float" at the top of the wall or does it have to float at the bottom, above the sole plate? Can someone direct me to a good reference for building floating walls? I am mostly concerned that I will not be able to raise the wall into place and hold it there while fastening it to the ceiling. 2-The builder installed insulation onto the basement walls by fastening it directly to the concrete. In some places it provides a loft of around 4-inches. I value the presence of this insulation, but in order to maintain its effectiveness (i.e. loft), I will have to build the frame away from the concete wall. This will reduce my final livable space considerably. What is the best way to maintain the insulation and maximize the final livable space? Can I use 2x2 lumber instead of 2x4 since the walls will only be supporting drywall? 3-How can I ensure that I am building a "straight" wall, one which runs parallel to the foundation wall, when the insulation loft will differ along the entire length of the wall? If I use a plum bob to define my wall "footprint", the footprint may not correspond to the foundation wall since the insulation loft will vary along the wall run. 4-Although most of the time, the walls will be running perpendicular to the upper floor joists allowing me to hang the walls directly onto the joists, there will be runs along which the wall will be parallel to the joists. In these instances, the nearest joist may be more than 6-inches from the wall. How do I hang a wall frame in these instances? Normally, I would build the wall on the floor, raise it to the correct position, and use blocks to attach the wall to the joists. Being a floating wall though, I am concerned that the blocks won't support the weight of the wall. Any ideas? 5-The joists are engineered I-beam type. Can I nail directly into these joists and hang a floating wall from them without degrading their structural rigidity? Also, if using blocks to join spans between joists, can I fasten the blocks to any part of the joist (e.g. the vertical part as opposed to the horizontal part)? Sorry if any of this is confusing. I appreciate any help you all can provide! John

I had an install drain tile system installed (approx. 80ft). This is where the floor along the footing is busted up, drain tile and weep tubes are added to the cinder block cores, and then re-concreted. My question arises because a 1/2" gap is left along the perimeter to allow any condensate to drain into the system. I plan on finishing these perimeter walls with an insulated 2 x 4 wall. I have noticed sow bugs crawling out of this gap. If I finish the wall, won't these bugs cause problems? Does this gap increase the chances of Radon problems? Should I seal this gap? I was planning to add a bubble wrap type of vapor barrier into the gap, and go up an additional 16" on the block wall, and install vapor barrier the "warm side" of the new insulated wall.