I have my own small homestead, so I have two cents for you!
Having a pair of breeding pigs will cost you more money to feed through the year than you will make selling piglets. Because I didn't want more than two pigs, I didn't look into how many sows I'd need to break even or actually make a bit of money toward feed. It's actually more cost effective for me to just buy piglets in the spring. That said, heritage black (aka large black) hogs have done a wonderful job clearing land!
On goats, Nigerian Dwarfs are excellent dairy goats and are, in me experience, easy keepers. The main thing is fencing, and knowing that they are going to clear what they want to clear (apple trees, respberry bushes, sumac) and not necessarily what you want them to clear (poison ivy). Chasing cars sounds dangerous to me, but they are very amusing to watch. And NorthFL Chick is right about having two. A buck needs a wether or another buck tonhang out with, and the does will need friends.