I would like to know if its possible for one to have a FaceTime session while also using another VOIP solution like BlueJeans or Skype at the same time, i.e. is it possible to be heard at the same time on both calls if active sessions are running on both of the apps?
While it is possible to have 2 simultaneous active VoIP calls (using different solutions) on your iOS device, it is not possible to be heard at the same time on both of them. As soon as you make the second call, the first one is put on hold.
You can switch between the two, but you can be conversing only over one call at a time.