Beautiful photo's, DD, and do not fear, we reared 3 pups together basically, one was born a month after the first two. I say rear two while you can. I'd probably do it again, even at my age. With my breed it's better watching two pups play together than be being heeled yourself by a bored little cattle dog pup bent on mischief.
We sleep all our dogs separately, and if doing obedience to develope a bond with them that is of course a one on one experience, I've never had dogs that bonded more to another dog than to me, ever. You'll be fine, you have all the good folk here to help you.