Here is my two cents as a landlord. I will almost always rent to people with dogs. I usually think twice about puppies, though. They are...well..pu ppies. They go potty in the house, they chew, etc. And two of them together can be a LOT!
Lab puppies are nuts until 2 or 3 and sometimes longer. I actually treat labs differently than other dogs for this reason. (When I'm considering renting to someone with a dog)
Having lived all over the country, I've found that the possibilities of renting with pets vary regionally and from city to city. Some places have a real pet-friendly attitude, and pet-friendly housing is easy to come by. Many aren't.
OK, this is getting long. But now on to two dogs in an apartment. I have two dogs in my two bedroom apartment. One is a one year old Flat-Coated Retriever mix, and the other is a 7.5 year old Newf/Chow mix. They are awesome in the house together, but this is only becuase the older one doesn't like to play. I wouldn't really be able to have multiple dogs in here that are crazy...its just too much.
So, the short answer is that a lot of it depends on the individual personality of the dogs.
hahah...ok..so rry that was so long-winded!