Hi New Dog Owner and welcome to the forum.
Firstly thank you for saving these dogs. They are very very young and this is why you are having these little problems.
Secondly having the two is actually better for them than having the one. Whoever told you this is impossible to manage knows very little so keep them both. They will ensure that equally they are socialized well. One will be more dominenant than the other and that is really ok. They understand eac hothers language and are taking their roles in teaching one another which minimizes a little of the workload for you. At the same time, you must take the role of the mother to ensure that they understand good canine behaviour. The best advice I have in regards to how to assume this role is to contact a behaviouralist and read about it as well. This will teach you and give you the understandings around helping them understand what is acceptable and what is not.
For the walking, this is challenging with pups whether one or two. Keep the walk brisk and quick. Encourage the walk in an upbeat tone with clapping and the 'good boys' in a higher, energetic tone. Keep moving. If one stops encourage alittle play and he will come.
I cannot comment really on keeping them separated in the crate at this moment. Personally, they need each other for warmth and security so I would not do it right now. By 12 weeks, I would however but close enough to see one another.
Ensure that your basement has windows and light....very important!!!