Currently accessing uncompressed .wav audio files, and wondering if it’s possible to play compressed audio? 16MB for our audio is a little large 
Not sure what you mean by “proper”. Do you wish to just use a conversion program, or do you need to do it in code?
Probably all platforms support Mp3 & vorbis. I am doing vorbis encoding in a back office tool for voice font development. There is a Js encoder which works great.
Yup I think all of them do.