How can I resolve audio interference effects due to wireless power transfer? 

Interference issue can be handled with proper shielding technique such as a ferrite plate under the RX coil to keep magnetic flux within a localized area. Further shielding can be achieved by adding a thin conductive plate behind this ferrite plate. These are largely system-level issues that depend upon total system design.  If interference is the concern, shielding at the system level is one approach that can be taken – the most cost effective yet sufficient method will depend upon the particular system.  In the most extreme cases, a conductive plate can be used which would suppress any interference.  But this isn’t necessarily required – it depends upon the particular system in question.