We're in the same boat! My puppies (both males) are 3 months old now..I've had them since they were 11 weeks. They are definitely a challenge..didn't think it would be that hard until I brought them home! haha. I did read about the littermate syndrome and other articles, but I agree and disagree with some of it. The dogs will become dependent on each other (obviously they will always want to be together), but I don't think it is absolutely necessary to do everything separate.
Ever since I brought mine home, I have been feeding them in separate places, crating them in separate cages is a MUST (they need their own spaces..even when they are little),
I do let them play together and depending on their attitudes toward each other at that time depends on if I separate them or not..sometimes I put one puppy in my bedroom with my husband while I'm playing with the other in the living room..if they get too "rough", I separate them as well..or if they get to crazy, I'll grab on and hold him for about a minute or two until he calms down. Now since they are older, they do listen to my husband and I so when I say "Stop" they definitely stop and calm down.
Toys- have LOTS and LOTS of them! And well actually, doesn't matter how many you have, they will always go for the same toy (just like kids!)..easy way to stop this is by simply pushing a different toy on one dog if they are going for the other one..it distracts them and they will play with it for a while.
Training-I did train them separately..mainly because they would just distract each other if I did it together. same with potty training..take them out separately so they learn to do their business quickly. If you take them both outside at the same time, they just start playing and will take a while for them to go! I can now take them out together and they go potty and want to go right back in.
Walks- the first time I took mine out on a walk, they actually did great, they walked right next to each other and close to us. I've heard different things on this though, walk together, walk separately..I guess I would do what works best for you and them!
All in all- it IS a lot of work..you will be frustrated numerous times a day more than likely but it so pays off in the end!! My advice is just to do what works best for you! See how they act together, see how they act separately. I truly don't see too much of the "littermate syndrome" with my pups. They bond together great, but they also bond with us too. Good Luck and let us know how it goes!