1. You can get the temperature waaay down, pretty much to freezing, without hurting the yeast. However, you won't get much (if any) fermentation at such temperatures. Different yeasts behave differently, but I don't know of any brewer's yeast that effectively ferments at near freezing temperatures.
2. You don't really need to rack to a secondary, but you do need to lager the beer. Typically, that involves keeping the beer at near freezing temperatures (typically 34F) for at least six weeks. Sometimes, you need to keep it longer than that to develop the crisp, clean, clear lager character.
On that, lagers should be clear, even dunkels. Even though it's fairly dark in the fermenter, you can tell the difference once it's in a glass. That clarity comes with proper lagering.
3. To get proper carbonation from bottle priming, you need fermentation. As I mentioned above, you will not get effective fermentation at near freezing temperatures. Keep the bottles at room temperature until they are properly carbonated. Then, you keep them in the laundry room at those colder temperatures.
There are a couple other things, though. Nearly every lager yeast does its best work around 50F, not at room temperature or near freezing temperatures. They also like consistent temperature. They were developed to ferment in cellars that provided those sort of conditions. If you are going to brew more lagers, give them those conditions, and they will make you happier.
Beer is good for anything from hot dogs to heartache.
Drinking Frog Brewery, est. 1993