I have about 30 or so that someone gave me in the 'bator. Stupid me, forgot to mark on the calendar the day I set them, but it was around 5/8 or 510. I have been turning by hand, never consistently, but several times a day. I slowed down over the past few days as I knew it was getting close. One started pipping today, quite loudly, and will break out overnight. So I figured I would stop turning the others, increase humidity a bit, and sure enough, can hear others picking away, so will probably have a mass hatch. Yeah, I too was candling over the past week, looked like nice healthy air space, but couldn't see much more, a little movement in a few and the interior picking, so will just let nature take its course.
I have hatched chickens and ducks, my first for guineas, but we have some we got day old keets from hatchery, they are out in an "adjustment" pen now and are eating from my hand. They get really ticked off when I walk away without talking with them, they want attention! So hopefully will be the come home for supper types in a few weeks. The farmer I got the eggs from has been hatching out for the past week or so, he set at all different times, but he has had a lot of success, very few failures.
As far as dogs, if you do as I do with the intermediate pen before you range them, and the dogs hang out around it and show them friendship, would say your chances are fair that you won't have a problem. Our dog loves all of our birds and is very protective, and will sniff around their pen and lie down next to it, and they seem to accept her. As someone said, depends on your dog and how tamed down you can get your young guineas. We don't want them to be too used to the dogs, of course, coyotes and fox look pretty similar, and we don't want them going up and shaking hands with them.