Rescue dog with surprise puppies...?

I rescued a 2 year old jack russell from someone who just wasn't taking care of it left it tied up outside or in a kennel at all times. she is actually surprisingly good tempered and i have been working vigorously with training and exercise with her she is a fast learner and just an all together amazing dog so far. but there is another problem she is pregnant with what I believe to be Jack Russell/ chi mutts. Im not planning on profiting from these puppies but do want them to go to responsible owners and the dog will be spayed as soon as she is ready after this birth as I do not plan on adding to the pet overpopulation. I just have a few question as i have never dealt with puppies before and any advice would be appreciated. What are some good techniques for stimulating and socializing the young puppies to make them good pets? I have 2 other dogs (min pin, husky/shepard) that they will be socialized with and a few Friends with dogs who comes for play dates all vaccinated. I read online to rub there toes and touch them all over and check there teeth to get them used to that kinda touch for vets and nail cutting? Im in the process of building a safe easy to clean whelping box at the moment its gonna be 45X35 and 12 inches high with hinged door, will they stay in there till they are ready to leave? (besides when i take them out to play) or should i make a a pen also with pee pads as a separate area for that? I have a large finished basement area for them. Any advice on the weaning process? what should be in a whelping kit? as well as what to expect? do the puppies poop right away i know with kittens the mother licks it out in the beginning what are some good vitamins available in canada for pregnant mothers or other things i can do to help keep mother healthy?. Ok that's all i can think of for now but like i said any advice would be appreciated