Jax is a great looking dog and I hope everything works out for you all and him.
I don't have any experience with having multiple dogs and Chunky usually ignores other dogs or tries to act submissive and then gets too excited when they get close and he jumps up scaring them off. All little dogs except his Big Chocolate GF "chocolate lab" up the street that he plays with. She is faster than him and also a young dogs so she wears him out.
I wouldn't mind having another dog but don't feel I have the time to put into one with me just starting back to work and already working 7 days and have no idea when that will end. I think it would be good for him to have a buddy other than me though.