It's crazy how your mind can make you perceive things, especially when your start thinking up some crazy shit from being high and that paranoia kicks in.
Sorry about seedlings, just plant some more haha.
You can get it off amazon or eBay. Also at local hydro store usually, Walmart will have emergency Mylar blankets those can work too. If your looking for doin it cheap just paint it white.
1. It's a reflective material like foil but not metal that heats up
2. As long as its dry, no
3. I would use a mh/hps setup, but cfls can work too. Youre gonna want at least 100w per plant but the more wattage the better.