You need to try taking their toys away, taking food away when they are eating, pulling their tail, ears, picking them up in an awkward way and not letting them go at first when they want to. It sounds harsh but you have to do it, because your children will at some point. You also need to put your hand in their mouths, and see if they pull away.
Agressive behaviour has nothing to do whether he is a pug or not. That's like saying all lop rabbits won't bite, but lionhead rabbits will. It's down to their personal character and life experience.
You are right, it really depends on the dog as to the length of time to potty train, but I doubt very much it will be six months! It might be longer than it takes a puppy though, as they might be more set in their ways.
Forgive me if I'm wrong, but it seems like you haven't owned a dog before. If you haven't I would buy a book about having Pugs as a pet. Dogs aren't as easy to look after as people think. You will need to learn about health problems, fleas, worms, ticks, mites, walks and most importantly - behaviour and training.
If you don't know how to handle a dog, you may well be too harsh (e.g hitting a dog can make it nervous and aggressive) or too soft (lots of owners get to the point where the dog doesnt know they are boss, and become lower in the pack than the dog). If you have sky, or can buy the series or watch it online, watch The Dog Whisperer.
His techniques are brilliant, but the important thing to remember is that it isnt just HIM that makes the dogs behave, it is what he is doing. Watching this will show you what happens when it goes wrong, and you arent leader of the pack. Then you can try and avoid the same happening with your dogs
you might not agree with some of what he says, and by no means so you have to follow it to the letter, but he has some interesting techniques that really do work. A lot of the episodes deal with aggressoive dogs and dogs with children too, so could be useful. He has a website : http
/www.cesarsway.com/
One last thing - a lot of breeds have health problems specific to the way they have been bred - for instance King CHarles spaniels' brains can get too big for their heads, and German Shepherds' hips tend to give way when they get older and they cant walk. I think (not sure) that pugs can have breathing difficulties. You will need to research any problems with the breed, because it can be very painful and expensive to deal with such a problem. Personally, I adore German Shepherds but know I could not have one again (I've had 3) because it is too painful to watch them suffer with a problem that has been bred into them, and have them put down before their time. Saying that, your (soon to be) pugs are fairly young so you shouldnt have to worry about them dying too soon.
Sorry I wrote a bit of an essay, just want to make sure you have all the information I can give you.
Oh and just wanted to say, he sounds lovely.