you'd be asking a lot of a single pole-mounted box that was already doing everything else, unless it was a really low-volume gig. a small bass rig would be really useful, or even just a small cab for your regular bass rig.
as for 1/4" vs XLR, the XLR out will be louder and will go longer distances without loss, but whichever one gets your signal to a close-by PA will do the job.
Guitar Repair Gnome
Alpha Music, VA Beach