Hi AuntieP. So nice to meet you, and a great big
to All Things Plants.
To answer one of your questions, I find that the hardy type ground cover sedum seem to do best is planted outside. You might want to wait until just before your spring begins. Same with the sempervivum.
There are several here that sell cuttings and can provide you with an abundant crop for propagating in the spring. Once planted they should take off growing quickly.
However, you must be very careful, this type of gardening (hardy succulents) can become quite addictive.
Would love to see a photo of the area you want to transform. Will you be turning it into raised beds?
There are also many other types of plants that will grow nicely with the hardy succulents. Like specie tulips, polygala, gentian, armeria, orostachys, rosularia. Oh my goodness there are just way to many to list.
Can't wait to hear more about your plans.