Marilyn, the above is definitely really sound advice. Do wait a bit before planting. When you get to leaving them outside, covering them with an old sheet or tee shirt will work should the temps really drop at night.
About your soil, if it's very thin ("a bit of dirt" as you say), and looks a bit too inhospitable to you, add a bit more of basic garden soil; although the soil in which they are currently planted might suffice.
My last garden had an abundance of rabbits (along with chipmunks and friends), yet they tended to leave the sedum alone. Of course, there was several other options for them.
