Hi Jason,
You can indeed replace the ball joints and the bushes on the wishbones but most people just put new bones on complete as its easier and quicker with less down time.
The ball joint and rear small bush can be easily done at home if you have a vice and appropriate bits of tube or big sockets. The big front one requires a press without question and needs to be orientated correctly as its fitted.
You have to drill out the big rivets for the b/j being careful not to enlarge the holes in the wishbone, this is best done on a drill press for accuracy.
It really depends upon how competent you are and the facility's at your disposal , its a job that many do successfully but needs to be done well.
Do not buy cheap wishbones as they wont last the year.
Brake wear sensor wiring should be clipped next to the abs wire and brake flexy hose and connects via a cylinder shaped connector held in a clip on the inner side of the wheel arch along with the abs connector. If you find it and its fubar, buy a new one or just bridge the wires to get rid of warning.
Hope that helps

Simon.