Wait, the cast sung the songs this time? I always thought they have a separate voice actors for singers, as in the case since Aladdin.
Nope. Voice actors do their own singing pretty often, actually. I'll list some of the exceptions I can think of:
Aladdin - Scott Weigner/Brad Kane
Jasmine - Linda Larkin/Lea Salonga
Pocahontas - Irene Bedard/Judy Kuhn
Powhattan - Russell Means/Jim Cummings
Mulan - Ming-Na/Lea Salonga
Hercules and Shang also had different singing voices. Other than that, it's pretty much all the voice actors doing it, as was the case with Frog, Tangled and Frozen.