Chromecast options inconsistency

Description

Sorry if it's not appropriate place but I've noticed inconsistency in the way chromecast options are used in vlc-ios and vlc-android. I mean those 2: "--sout-chromecast-audio-passthrough" and "--sout-chromecast-conversion-quality"

In vlc-ios they are used as global libvlc options and there is a comment:

/* the chromecast and audio options **cannot be set per media**, so we need to set it per
 * media player instance however, potentially initialising an additional library instance
 * for this is costly, so this should be done only if needed */

But in vlc-android those options are set as both global libvlc and per media options

Questions

1. Should chromecast options be set as global libvlc options only?
2. Do they even work when set as per media options?
3. (Bonus) Do they work when you cast an audio file? (I'm not sure if "--sout-chromecast-conversion-quality" works only for video)

Another minor issue I've noticed, when audio passthrough is set per media, the preferences default value is "true", it should be "false": media.addOption(":sout-chromecast-audio-passthrough=" + prefs.getBoolean("casting_passthrough", true))