I like these ideas - keep them coming. Please note that all these ideas will also require translations into various languages: if you happen to know someone that could help with that (over 9 languages!) then please ask them.
@Valki Can you use your first / second post as an overview of the various ideas?
@KaletheQuick I think voices would not be used a lot in practice - it will def. be an opt in instead of an opt out. People don't even like the sound of the pings, let alone a voice that gets spammed.