We have 3 females, and females will fight more than males will usually. Two were bought at the same time but were different ages by 5 months. They would fight every once in awhile but not much anymore. I only had to "pin" them down once and after that if they fought I would just say "hey, knock it off" and they would stop. I can usually see the the fight coming and stop it before it starts. Now that they are older, everyone gets along fine. It is always best to have a male and female, but both sexes can live together, it's just how you train them and show them you are the alpha. I guess I'm lucky because I have grown up with dogs all my life and have always been 'in tune" if you will, with dogs, for lack of a better explanation. haha I kind of understand them and just have a way with them. I have learned a lot though the years by watching and listening to others as well. As stated earlier if you have never owned a dog before it may not be the best idea to have two males. But with work and doing your homework it can happen. It helps to raise them as litter mate as well, just my opinion, because I have done it.
As far as the play fighting, pups will play and should be able to play together. They will bite each other and this is normal. It's when they start to get louder and more excited, is when you step in to stop it. Give them each a chew bone to redirect them for a little time out. It is healthy for them to play together. You will know if they are fighting and if the playing turns into a fight you will now because their growls will be a different pitch and louder. When that happens you may have to pin them as describe above and don't let them up until they both are submissive. Anytime you are not sure of something or have a question please let us know. We are always here for each other. There are a lot of opinions out there as to how to raise or train dogs and some are better than others, you need to find what works for you.