For some reason when i have my mic on and connect to a team, sometimes the "participant" box populates and some times if does not. It seems to work with some people but not others. is their something that they have (or not have) that could be causing this?

It depend on if the individual player has voice chat enabled (or not). Some players prefer the use of third party utilities such a 'Teamspeak'... And some players want to avoid the additional network connection overhead that voice chat demands...

I had thought that as well, i asked ,the people whom were not connecting, if they had chat enabled or if they were using a secondary voice chat system. they said no. if this is the case is their someway to populate the "participant list"? Also on a side note how can you set up fleet voice chat? Can it be done on the sto client or does it have to be on a third party server?