You could wire in series, say from a 50v transformer, but you are limited to 11 led's, no more can be added, and none can be taken away, if one fails they all fail.
So you really need to wire in parallel, from a 4.5 transformer. You will need to check wattage on each lamp and total up. If possible the switch should control the transformer feed and not the output lighting feed, otherwise you may get vd probs -
not sure, but led's should work on ac or dc, all my led's run on 230v ac, yours run on dc...fluros should not be ran on dc, even though they will work, for a while!