I cannot speak to your question about the self adhesive tiles, but I can provide advice on the floating floor. Take a look at this thread...
You can also do a google search like...
"floating floor site:www.airforums.com"
and you will find many threads.
Cutting and ripping planks to go around 90 degree corners is just a matter of making measurements and adding the necessary 3/8" to allow for expansion and contraction of the flooring material. Measure the distance you need to rip a plank and the distance you need to cross-cut it and lay it out in the plank. Make your cuts cloes to the intersection with a circular saw and finish the cut with a sabre saw. It is all pretty simple. You just need to take your time. And as my dear old dad always said..."measure twice...cut once." You could also make a tar paper template to get you close and trim in small increments until you get the plank to fit the way you want to.