What kind of cable angle you want will depend on how your pickup mounts. On my electric the jack is on the bottom, so an angled plug is easiest. Honestly they're so common, I'd just wait until your pickup shows up and then go to a guitar center or something similar and just plug some cables in and figure out which kind you want. Either one will work, its just a comfort thing.

If the DJ is asking for an XLR cable I assume they're trying to plug you straight in to a mixer/PA. If thats the case you're also going to need a DI/pre amp. Otherwise your instrument is going to be too quiet to ever make it to the amplifier. There are many, many options but I just use this cheap little guy https://www.amazon.com/dp/B0002M66SG?psc=1&ref=ppx_yo2ov_dt_b_product_details

I'd also highly recommend an impulse response pedal or something similar. Not necessary, but that will emulate an actual amp/cabinet and can really add a lot of depth to your sound instead of the kind of nasally sound piezo pickups tend to produce on their own.

Another option you might want to look in to as well, are the pickups that are really just a microphone mounted to the instrument. They're not good if you're playing on a loud stage because they'll pick up other instruments, but they will give you a much more natural sound than a piezo with less work. But if the wedding is going to be loud, stick with the bridge pickup.