I wanted to ask you guys if it's possible to animate only the face expressions including lip sync(using webcam) in Adobe Character Animator and export the face in After Effects and parent it to the body? Is it a good way to animate?
Can I just use Adobe Character Animator for lip sync(with a audio file imported from Adobe Audition) and then export in After Effects parent it to the body to ease my work?
What's the best way to use Adobe Character Animator with After Effects?
Yes, that should be completely doable.
You can either use dynamic linking to bring the animation across, otherwise if you export a video file pick a format with transparency support. (Easier than trying to green screen it afterwards.) eg QuickTime /GoPro cineform with alpha.
Using dynamic linking keeps everything in sync nicely - just drag scene from ch window and drop into AE window. Easy! But if performance is bad, then consider exporting a video file. Then Ae is just manipulating files.