There are hundred of threads about pork butt so have fun reading. You've got time.
Whatever you do, use Chef JJ's finishing sauce. It makes the meat flavor "POP" and folks can control how much they add to their meat. Just use the search bar and it pops right up.
BBQ sauce? I'll add a little once it is pulled, but not much, preferring to serve it on the side for folks who want sauce. I like to taste the meat.
Coating it with rub the night before, wrapping with plastic wrap, and letting it sit in the fridge overnight can pull rub flavors into the meat. That is a popular way to do it. I rub it just before it goes on the smoker.
Woods? That's a personal preference all the way. I like hickory and cherry together, but apple and pecan are popular choices too. Since you are using lump charcoal don't sweat it if your smoker wants to run hotter.
A pork butt is one of the most forgiving and tolerant cuts of meat you can stick on your smoker. It handles everything from low and slow to hot and fast then still comes out tasting wonderful. Heck, just for grins and giggles, one time loaded the meat on the smoker at 225F, over the next several hours the chamber temp climbed as high as 310, then over a few more hours it fell back to about 250. Still came out delicious. Bottom line, don't sweat the temps. You'll get a TON of answers on the temps people prefer to use to smoke roast their butts. The pork butt likes them all!
An overnight smoke can be an issue on a smoker that isn't set and forget. The last thing you want is the smoker going cold while you're snoozing so plan on just napping and set an alarm every couple hours. If you want it done more quickly you could easily crank the temp on the smoker up to 275-300F, smoke it until it reaches an IT of 165-180F, wrap it until 203-205F IT, and be done in roughly 7-9 hours. Or like Bama BBQ said, cut it in half. More bark, less time.
I've smoked butts a variety of ways. My current preference is liberally dry rub (no mustard or EVOO) and smoke at 225F with hickory and cherry to an IT of around 180F, then wrap it with a little apple cider and crank the temp up on the smoker to 300F+ so it finishes quickly. I get a great bark and can save the jus in the wrappings to use on the meat. I don't spritz butts.
At the end of the smoke taste the meat once it is pulled. If it needs a little more flavor throw on a little additional rub to give the meat a little more flavor depth. You can add the jus too.
And don't forget Chef JJ's finishing sauce!