The studio has Pro Tools 8 & Logic 9 so if you are sending sessions in those formats there is no need to bounce the audio, just send the compressed/zipped trimmed session file
It's better to get rid of any audio that is not used in the song, this speeds up the file transfer process. Your DAW has a function to select unused audio and then you can delete it.
Export the audio from your DAW so all the files start from the same point.
If you're uploading a song from a DAW it's better to compress the session folder and send it as one file.
The Upload takes a maximum of 2Gb per file so if you're song is bigger you will have to split it up to be within the size limit.