Thanks, I really tried to make everything as serviceable as possible - ideally with parts that are on the shelf at the local parts store.
The filter's output is a male quick connect, so I used a female quick connect to -6 AN fitting, like Vibrant Performance # 16886. It found a pic on my phone that shows the plastic piece is blue, so might have actually been Evil Energy brand, like this: Amazon.ca
Then there's a female -6 AN to 5/16 compression fitting connecting the steel line. Again, probably Evil Energy: Amazon.ca