This would be the normal workflow based on your requirements.
1. Create the 10 2D characters one by one and save each one in Content Manager under Actor > Custom tab > 2D Actor (Press the + ADD button at the bottom of Content Manager).
2. Load the first character and build your project by adding speech, facial animation, music and add a background if required.
3. Save this as a Project file in Content Manager under Project > Custom tab > 2D Actor.
4. Now with the saved Project loaded, just load each of the other 9 saved characters from Actor > Custom tab > 2D Actor and they will replace the existing character but will retain the speech and facial animation. When played back the project will be exactly the same but just have a different actor talking.
I hope this helps.