Finally got a good(ish) picture of Lucy and Ethel together. I figured out the trick is to wait while they are eating - which is when they are closest to being still.
Lucy is proving to be quite an adventurous girl, with one very impressive attempt to escape the playpen - a great leap from my shoulder to the top bar of the "pen." Luckily I managed to foil her plan.
Ethel is turning out to be the more "snuggly" of the two - she's the first to come when I open the cage and immediately wants to run up my arm and hang out. Lucy is still on the squirmy side when I hold her, but Amy at PX rattery says she should settle in as she gets older.