Appeon Web 6.6 developer license will come with the Mobile module and vice versa. Then you will be able to have both: Appeon Web and Appeon Mobile on your development machine. 

However, when talking about the Application server, you must use different machines per version: one server for Appeon Mobile and a separate server for Appeon Web.

If you just have one server available you may use VMWare and create an instance per version or purchase Appeon Universal version (includes Appeon Web and Appeon Mobile)