So I bought the $10 dlc bundle and decided to play the new maps. I specifically selected the dlc maps so I could get into them faster. I noticed that when I do that, the match has 1 to 4 players. Am I doing something wrong or do I have bad luck? Do the dlc maps appear when doing normal matchmaking? 

It could be due to a few things, like time of day and the recent gift of different games to play through.

I don't really know the answer to your questions, but my experience tells me that if you decide to split a community by selling maps.. more people will likely be less inclined to purchase said maps. As you probably know, we're not talking COD or BF numbers to fall back on either, unfortunately : /