Lower control arm question

It totally depends on the type bushing used. @BergmanAutoCraft sells Delrin bushings with custom pins that go with them. They do not use the outer bushing shells, so you remove those and press the bushings directly into the control arm. Most polyurethane bushings require the shells to be left in. When using factory style replacement rubber bushings, the old shells must be removed. I use an air chisel, but I'm good with it. I keep the chisel SHARP and have been doing it for better than forty years, so I don't damage anything but the bushing shell. The other two methods you mentioned work well, too.