so I'm going to record direct input but apparently this bass is an active bass (which I think means there's a pre-amp built into the bass. Can I just plug this thing directly into my profire? Trying to be cautious so I don't break my interface or his bass.
Yes, you can plug it straight in - no instrument input should be damaged by the output from an active bass, though you may have to take care to avoid clipping. Switch the input to 'Inst', and adjust the gain control to a point where you have plenty of level but where the clip light isn't coming on. Use the "Pull : -20dB" option on those controls if you need - or you can always turn the output on the bass down.