The scratch track thats in that 5 minute gameplay video is indeed just me, with a mic.
I don't really want to waste anyone's time recording dialogue that's not going to be used, so I record everything myself first, and then email the script to the voice artist once I'm sure it's all working. Then I just replace the Sound Files with the vcice artists one.
I'll take another look at the computer voices. Right now I'm using FLStudio, but I'm sure there is a better alternative. The game does have Dialogue Portraits', so should make following the voices easier.
I'm a 1 man team, apart from the voice artists, of which I currently have 2 for the main characters. For resources, I am a professional 3D artist, so creating the artwork is really my main focus. Everything else, from the music to the sound and programming has been a learning experience for me!