As you've read, mp3 streaming does not work in many Android devices. Only AAC encoded audio streams work in those devices. There are new devices and OS versions all the time of course with changing specs, but many Android devices currently in use do not support streaming mp3. There is not a work-around in Wowza.
Android devices cannot play MP3 streams over RTSP/RTP in any combination (audio/video or audio only). Android devices that support Flash player 10.1 can play MP3 using RTMP or Flash HTTP. When streaming to an Android device using RTSP/RTP, the RTP portion must flow over UDP. Android does not support RTSP/RTP interleaved (RTP over TCP). This means if UDP is unavailable for RTP playback, RTP over TCP will not work as a failover and your stream will not play.