My rats had babies. how long till?

My 2 female rats just had their litters. One had them this past thurs-so about 5 days ago now. The other one had hers yeaterday,a little over 24 hours ago. they are of course in seperate cages. I have a couple questions. The first rat I have only had for about 5 months now. She is not well trained. she bit me when I went to changer her food after she had the babies. It was very bad, needed stiches and then had to be drained becuase of subsiquent infection. The other rat, I have had for about a year and a half or so, and she is well trained, comes and goes in/out of her cage as she pleases (till she had the babies) and she always comes when called and loves me. She does not bite, and allows me to pet her babies and such. No prob. How long till the other rat allows people to get in her cage? I will not be able to clean her cage till she is not so defensive of her babies. Also, how long till they wean? and also when will they grow thier fur? On the first litter, you can see the dark patches and light under their skin, but no fur yet. i will be keeping them till they are ready to go, I am keeping a few of them. I have other people lined up for most of the rest. when will they be able to go home with their new families? Please help address all 4 questions if possible! thanks!