Hello,
regarding your questions, audio and video works generally well in the latest Mobile version in sites with Moodle 3.2, in previous sites you may encounter this kind of problems.
Unfortunately our core team do not have the resources here to help people use the open source code version. We provide a service where we can customise the app for anyone who needs it. This service helps fund the improvement of the app in general: https://moodle.com/mobileapp/
Regards, Juan