When Arvel "fails" his boost because he would overlap his opponent, it's said to resolve by partially completing his boost. Do the two ships have to touch or can they be separated by a thin margin to still take advantage of range 1 from both ships?
You would move all the way forward to touch, just like partially completing a maneuver. So Arvel would get to enjoy a range 1 shot thanks to his ability, while his target would be shooting at range 0.