Here's some snapshots from our terrarium. After a little browsing around your site, I'm reasonably confident that these are echeveria maybe a pachyveria. I also found the pruning page and believe that in order to get some nice large rosettes, they will need to be pinched, low.
Thanks, again, in advance!!
Drought Smart Plants reply:
Hi again, Ken - glad you could find out what they are. Pruning (or pinching, it's called if done really early) will certainly help to keep the plants compact. Keep in mind that you will probably cause it to break into several rosettes, not just one, but they will definitely be lower to the ground.
Don't discard the parts you cut off, as they will again form a new plant.
Picture #2 looks like some kind of Sedeveria (a cross between Echeveria and a tender Sedum). The rest of them I think you've got the right identification, but it's hard to tell since they're so small. As they gain in stature, they'll be easier to compare to mature plants and identify them.
Have fun with your project!