I live in a remote area where we have Black bears, coyotes and all. I left my hogs loose in a 4 acre pen with 4 foot fencing and had no problems ever. As for goats and pigs getting along...I don't think that is a good idea. If given the chance the pigs would eat goats.

I would keep the pigs and the goats separate as well. You could get you a couple of portable pens and move them as needed. Though don't be surprised if the pigs escape from the pens and go wild.