[Sage J. Fox]

Basically, I'd like to set up little bits of (triggered by map events) banter between the actual player characters. Is there a way to reference players in a way so the voice files will play from them, with the proper lip syncing and all that? I'm assuming it's somehow possible seeing as they can do it a bit on their own (a player dies and all living players give their little reactions, they say ow when hurt, etc.).

I've tried having !activator as the source entity for an ambient_generic, but it still plays from itself. And I am aware of !rndplayer as far as the description goes.

[Danny]

Really you should turn to plugins, making or finding them from either SourceMod or EventScripts.

If you're insistent on using an entity such as ambient_generic, there is an input for it ( SourceEntityName <targetname> ) that you could use to play it from a named client.
I believe it also supports lip syncing. Info on Ambient_generic

Alternatively, if you know any python, or C/C# you could go the more global route of learning how to use SM or ES. Really you could even could code in C++ if you like loading .dlls and hooking straight to source.

An EventScripts python example of how we would do the above, and have lip syncing:
es.emitsound("player", id, soundfile, volume, attenuation)

[Sage J. Fox]

I had a feeling it'd end up being best done outside of the map itself. It's by no means going to make or break the map if it's not there, and it wouldn't really be that much of a bonus to go through all the trouble of making and then having to include all sorts of additional files.

Thanks for the information, though. I'll definitely keep that in mind should future maps I work on need need it.