I am going to guess that the ingame 'beeps' are 1 or 2 second midi files.
What you are going to want to do is find them (wallmarket knows where they are)
Open them in a midi program that can export .wav and import soundbanks, Sonar 8 by cakewalk does this, so would any other recent DAW
From here, import the midi and one of the ff7 soundbanks that are somewhere near midi.lgp.
record those bleeps and bloops to .wav and convert to .mp3