Quote: "All sound files for GG must be in mono?"
no, it's just stereo is assuming it has depth in the audio already, mono is considered "flat" so GG uses that type as it's default for making fake depth of sound
Quote: "Can they play at the same time? If Yes, how many can play at the same time?"
yes multiple sounds can play at once - no idea what the limit is but i doubt you're going to reach it for any normal game
Quote: " Does it matter which sound positions (0,1,2, etc) are used for each entity?"
no, the slots are just so you can play different or multiple sounds from 1 entity - it only really matters in that you need to keep track of which sound is in which slot for the purposes of playing them later
Quote: "Finally, if the script (attached to the entity) plays or loops the sound,
then the near and far effect is automatic?"
it should if the sound is in the correct format, otherwise you can fake it via GetPlayerDistance(e) and SetSoundVolume()
Quote: "PS... what does SetSound(e,v) do?"
i've not actually seen this used, would be curious to know myself but i think maybe it was intended to swap the sound used in PlaySound() - like PlayAnimation() - however PlaySound takes the slot while PlayAnimation doesn't