.44mag and .45-70 would be my recommendations. The Gov't will be stiff for your young girls, especially in the lightweight break action rifles like the Encore, so the .44mag might be a better option. Many of the others will work just fine, but for what it's worth, those two will be easiest to find in many different loads, and offer the best performance (i.e. .44mag over .45colt or .357mag for performance, .44mag over .357max for availability).
The .444M or .450M are great options as well, but the .450 is generally going to be hotter than factory .45-70 loads, so recoil impulse will be even worse.