Puppy with older dogs?

I'm moving into a house this september and planning on getting a puppy (lab). If i'm stupid then please tell me, but there are already 2 dogs there(renting a house with some friends), a small beagle mix and an old boxer. The beagle is pretty mello as far as beagles go and the my roomate rescued the boxer from the pound. He's smaller and the calmest dog i've ever seen. The vet guessed he was around nine so he's an old boy who's just happy to sleep and be petted after the previous life he had. I am concerned how throwing a puppy into the mix would be. I know it really matters on the dog's personalities but are there any general patterns or concerns i should have. I know its nuts to have 3 dogs but i've been dying to get one for a while and now i finally have the yard for one and my roomates said they had no problems with the it. The backyard is gonna be a minefield though. Thanks....... <br>

 

Thanks, I'll be finishing up grad school this year and should be home most of the time writing my thesis so i can monitor everything, but i'd still be worried when i leave.&nbsp; Is there any concern about my dog picking up bad behavior from the other dogs?&nbsp; They let the beagle climb on the furniture and treat the leash as a toy.&nbsp; I assume that simple corrections would be enough to let my dog know that that behavior is not allowed for him.&nbsp; Sorry i'm so naive, i plan on doing lots of reading this summer, and my dad and his buddy have trained a few dogs as well.&nbsp; I also know of a tainer close to me that i can always work with.&nbsp; <br>