The tenderloin will finish far sooner than the butt and should be pulled at no greater than 155° internal temperature. I'd be tempted to pull it even sooner, particularly if I were planning to add it to another dish, reheat it, or otherwise further cook it in some manner. The National Pork Board says it's safe at 145°. The butt you can pull at 195° and it should be excellent. Both the loin and the butt can be smoked reliably at 255°.
The only 'problems' might be that the loin may be overly smoky depending on how much wood you're using for the butt. Likewise, if you only use a little wood, when you open the door to pull the loin you're going to lose heat and smoke so that butt might take longer and not be quite as smoky as planned. I'm sure you can find a balance, though.
