I'm thinking of adopting a young female Presa Canario and currently have a male pomeranian. Any advice?

Their breeds has nothing to do with it, if the Presa gets along with other dogs and your Pom has no dog issues then you should have no problems. I would suggest talking to the family and asking if they would bring their dog to a park and meet with you and your Pom, to see how they hit it off. If everything goes well see how they do at your house. If there are no problems then it will be fine.