lower control arm bushing problems

Definitely have the weight of the car on the arms before you torque the nut. Any suspension bushing wont last long if it's not in the normal ride position when it's tightened. It twists the rubber as soon as the weight is on the component & rips it to death from there.
I drive the old ones out with an air chisel or a ball joint press (even a cheap Horrible Freight one will do). I wouldn't recommend burning it out unless you like to breathe in a lot of smoke, keep blowing out fires & like all the floating bits of rubber soot getting all over everything, not to mention the stink. It just makes a mess. Plus if you have to reuse the metal shells you risk damaging them with the torch. The heat will anneal the metal & make it softer & distorted. Torch would be my last resort.
Regarding the UBJ, the tubular arms may not have the same amount of interference in the threads where the ball joint threads in. You may have to use some red loctite(permanent) on the threads or create some interference of your own in the threads. The interference in there to help keep it from working itself loose.
Good Luck!