This is cool! What, exactly, is the role of VNC in what you’ve got going here? Is it just a way to get a keyboard and mouse controlling your phone?
Since we are using qt with c++, it may be possible for you to simply build a proper android application using somewhat standard techniques, since qt and android support this kind of application now.
Let us know how it goes, this is very neat! Does receive audio work? What audio back end did you select?
VNC does not support sound . You can use PulseAudio to move sound over SSH, though, which may be better than nothing for you.
Anyhow, a better solution which is faster and supports all the stuff you need is nx nomachine. It is also natovely on windows, linux, mac, android and ios.
It also runs in a web browser if you like. can run over ssh too