Hello. I'm new here, but not new to rats. I am, however, new to babies, and because I had no intention of having any could use some advice. In hopes that I wont get flamed, I'll give a little background...
I had a pair of rats, both of which were very sweet. I got one a good while ago as a rescue, and the other I got as a companion for him. About two months ago, the older of the two died. Immediately upon this happening, the other became visibly distressed and depressed. I decided to get him a cage mate. The local humane society had a few babies at one of their satellite adoption centers, and I was lucky enough to find a little boy there who I absolutely adored. He was very young, about three weeks old I think. Light grey with dark grey spots and blotches, and a dumbo. Showed no signs of sneezing or allergies or anything, but I decided to keep him at my boyfriends house for a month of quarenteen just in case something showed up, and also until he was showing (cough) slightly more obvious signs that he was a boy.
Sure enough, he started to get a bit of a bulge, and after a month, had a very smooth introduction with my older boy (a hairless.) There was a little fighting for maybe 20 minutes, but I haven't seen them fight since. Really, they're not too interested in each other. They sleep together, occasionally wrestle, but no unnatural signs of interest. Sounded like a good sign to me.
... Long story short, my little boy, bulge and all, suddenly has a very wide belly and obvious teats. He's been with his cagemate for about 2.5 weeks, three at the most. Not sure how on earth this happened, but I'm trying to be responsible and prepare for it the best I can. Luckily, I'm financially stable, and at least for the next three months have lots of free time. (summer break hooray...) I have a large variety of cages and tanks in my attic which I'm sure would be fine for birthing. (I'm thinking the 20g long with a mesh screen, though if that seems a little too small I can upgrade to the 29g.) I'm not sure what kind of bedding is best. I already know the standard rat rules (no woods, dust free... currently I use carefresh) but I've read some things about that sticking to babies.
I also know I'm going to have to try to find good homes for these babies. I figure I'll wait until after they're born and I know how many to start that one.
Anyhow, now that there is some back story that will hopefully prevent me from gaining the stigma of irresponsible breeder, here are my quick questions.
Is there anything I should be particularly concerned about considering the very young age of this girl? She's only about two months old. The daddy is a little over a year.
What kind of bedding/substrate is best for babies?
And lastly, what age would you consider it safe to find new homes for them? The opinion I've formulated is that they're safe to go away from their mommies without any emotional damage at about five weeks, but of course I'd respect the opinions of people who have done this before over my random reading

I'm thankful that I at least have two very beautiful babies. It doesn't matter to me what they look like, but I do home that it will be easier to find them good homes since they will be so unique. Of course, I have no intention of giving them to anyone who I have any doubt of, and unfortunately, don't know anyone who I wouldn't' doubt. I've never had much luck with placing local rescues in this region.
I'll keep you up to date, thank you for any help you can offer.
Also, just as a side note, I fully intend to get my girl... (her name is Mr. Hibbleton, I suppose I'll have to change it to Hibbie now or something) spayed after this ordeal, as well as any of the females I can't place. I know it has more health benefits than neutering, and I have a very great vet who has done some surgeries on rats of mine in the past.