Your dogs are so cute, Niki. Best of luck with adopting your new pigs.
As for dog/pig safety, I use a safety gate that I made myself. Or should I say, my mum made. It slides between the door frame and two rods, each placed on the door frame. Works just like a baby-gate except it is a very solid structure and you slide it up, instead of swing it open. The door can also be closed while the gate is in too. It's 2 cubes high and covered, so no dog can see in and no pig can see out.
Our dogs are never upstairs (where the pigs are) unsupervised since they are both elderly and are blocked from using the stairs by proper child safety gates. We carry our nearly-16 year old Shih Tzu up (he's blind, deaf, daft etc.) and our 12 year old Border Collie X follows. Bo (the Shih Tzu) wouldn't attack since he can't see anything more than a centimetre from his face, but he would definitely stand on them (or fall over them more likely). The other one never gets near my door at all. I send her away and she runs away and doesn't come back. She's a very scaredy dog despite her size.